As for SMT, the best starting points are probably Devil Survivor on DS/3DS (because of familiarity with FE), SMT IV on 3DS (one of the easier entries after you get past the hellish beginning), Strange Journey on DS (it will give you experience with first-person dungeon stuff if you want to get into earlier entries down the line, plus the story's good), or Nocturne/Lucifer's Call (if EU) on PS2 (this is if you want to launch yourself headfirst into the difficulty the series is known for).
Beware lots of words.
[spoiler=Devil Survivor]There are two Devil Survivor games each on DS and 3DS, with the original versions on DS and updated rereleases on 3DS (Overclocked and Record Breaker). The original games are alright, but their 3DS versions are better. The two games aren't connected story wise, so feel free to pick up either one first. I don't think any of the games are on the eshop, so you'll have to check gamestop or amazon or something. The familiarity with FE comes in with there being character's you control on one a battlefield resembling FE's with the grid and stuff, just diagonal, and when moving you can use healing skills and attack the enemy. Battle has you and your demons select an action each (attack/use a skill/defend), and then both sides perform their actions in an order based on speed/agility. If you/the enemy hit a weakness/crit, you may be given an "extra turn", where all combatants who have an extra turn can perform another action of their choosing.
The characters have stats that go up on leveling, with the main character's being chosen by the player (a common thing in most SMT games), and they can be given skills that have been "cracked" from an enemy they have defeated. When not in battle, you get a menu of the possible locations you can visit, and if anyone is there. You also get a menu to do stuff like equip skills/assign demons to a team, check email/texts, get demons, etc. Demons are obtained through an auction system where you bid on a demon, and then new ones can be obtained through fusion. This is also one of the few SMT games to allow you to have multiples of the same demon.
There aren't really any newcomers' traps in these games. If you need money/experience there's almost always a free battle to that that doesn't pass time. I guess don't get too attached to demons, as they are meant to be fused, used until you can fuse something better, and get fused off. That applies to all of SMT though. In Devil Survivor 2 there's discount social links with your party members that can give them resistances, abilities, and new demons to be unlocked for fusion. Also you gain character's throughout the story, and there's usually some only playable in certain routes, but the thing is that you may lose some characters through story line death. It's possible to not let them die, but on a first playthrough someone's probably going to die, and you might just have to accept that.
[spoiler=SMT IV]Shin Megami Tensei IV is on 3DS, and it is on the eshop, generally at about $19.99 there and $24.99 for physical pre-owned at gamestop (can't find it new on their site). If Europe, eshop is your only option. 3rd person on the field, you have a moving icon in the overworld, 1st person battles with sprites for the enemies. Now, this is one of the easier entries thanks to a multitude of options for skills and demons that open up once the world opens up. The problem is, before then, you're gonna be getting you ass beat somewhat often. SMT IV is one of the few SMT games that doesn't have an endurance stat. So early on you're not going to be taking too many hits from enemies without needing healed, and that can quickly end up in a game over. Now when you die, you'll be taken to Charon, who can revive you if you pay money/play coins, or you can deny those and get kicked to the title screen. Luckily you can save anywhere at anytime (provided it isn't a cutscene/battle of course), so unless you've been neglecting saving, which you really shouldn't in this series, it won't generally be that bad.
Now there are a rough couple bosses before the world opens, particularly the one at the end of the beginning dungeon, but once you're past that you're golden. The world map is a bit confusing, and it will stay that way until you get used to it, but it's manageable. Battle system is turn based using the press turn system introduced in Nocturne. For each character/demon on either side, that side gets a press turn icon (generally 4 for you and 1-4 based on how many enemies you're facing, with bosses usually having 2-3). When a unit performs and action, an icon is taken away, and when all icons are gone, the phase switches and it becomes the other team's turn. If a weakness is hit, a crit procs, or if you pass your turn, the icon becomes a blinking icon, which pretty much gives another action. This can be stacked to get as many as 8 actions per turn. If an attack misses or is nulled, an extra icon is taken away, and if the the attack is drained or repelled, all remaining icons are taken away. These rules apply to you enemy as well, except for the passing because the enemy doesn't pass. Now, if an attack crits/hits a weakness, there is a chance that the unit may get smirk status, which sharply raises attack, hit/evasion, guarantees a crit, and turns any weaknesses into neutral damage. Also if all of one side is smirking, some HP and MP is restored. So smirking can really change the tide of battle, especially if a boss smirks. Because of this, not many battles last that long for either side. Smirk status goes away after the next attack, if inflicted with an ailment, or after a few turns.
As for newcomers' traps, there's the getting too attached to demons thing, and the difficulty of the the entirety of the first dungeon, along with stat builds (sorta). Just as a preface, Strength affects the damage done with your sword/knife/spear/whatever and helps a little bit with the power of physical/gun skills. Dexterity affects the damage done with you gun (when you get it) and greatly affects the power of physical/gun skills. Magic affects the power of magical skills, both damage and healing (to a lesser extent). Agility affects hit/evasion and helps turn order (generally a point per level lets you move first unless your demon is particularly speedy). Luck affects stuff like ailment hit/evasion, crit rate, etc. So generally you want to run either a Dex build (harder early game due to fewer skills and probably not hitting weaknesses, better late game because you're critting out your ass and smirking every other turn, and if the enemy nulls phys and gun (not many) you have more slots for support than magic) or a Magic build (easier early game thanks to lots of options to hit weaknesses very frequently, not as good late game because enemies and bosses may not be weak to stuff, but you can still do good damage/support) with some Agility and Luck.
Also the alignment system is a bit wack. There's three routes (and an earlier bad end), and your decisions throughout the game push you towards two of those routes, with a neutral in the middle. The thing that bothers people is that because of decision right before you get locked on a route, you may be too neutral to go neutral.
[spoiler=Strange Journey]Strange Journey is on the DS for $17.99 from gamestop, though you'll probably have better luck just buying from amazon. It's 1st person dungeon crawling with small breaks at the base with menus. This is one of the few SMT games that doesn't let you choose the main character's stats upon level up, and it is RNG based from a questionnaire at the start of the game that gives one of your five stats Strength, Magic, Endurance, Agility, or Luck a slight growth bonus. The game can be a bit hard with annoying dungeons and the good ol' fun of "if the protagonist dies, game over" present in most SMT games.
Battle system is turn based with you selecting actions for your demons, and then you and the enemy performs actions based on agility. No press turn and it's more like other RPGs (and some SMT games without press turn). When you or a demon hits a weakness, all others of that same alignment do a co-op attack for some damage. When fusing, there's no rerolling for skills unless using a demon source, obtained when you've maxed out the scan of a demon through fighting with and/or against it a lot. You get materials to make and buy better weapons, armor, items, and apps from defeating enemies/bosses. Saving can only be done at base or at mini terminals throughout the dungeons. There's some annoying things, but it adds to the charm and appeal of the series. Plus it has good atmosphere and story.
There's an alignment system through your decisions throughout the game, and the three routes all have annoying final bosses. As for newcomers' traps, don't get attached to demons, expect deaths and frustration (especially from bosses), and each dungeon has a central gimmick except for the first and fifth (IIRC). Also late game your protagonist literally cannot match up to the damage of your demons, and so he turns into a support bot. Luckily using items is always the first thing to happen in a turn, no matter what.
[spoiler=Nocturne/Lucifer's Call]Nocturne is on the PS2, though it's also on PSN. Try amazon if you want the PS2 version. Nocturne is quite difficult, with confusing dungeons, game over on protagonist death, rough bosses, the works. The protagonist gets no weapons or armor and so he relies on various Magatama found throughout the game from bosses or special shops. These Magatama raise some of the protagonist's stats, gives him weaknesses and resistances, and once he reaches a certain level, he can learn a skill. Thankfully for these it's based on once he reaches a certain level or above he learns the skill, and doesn't need to have a certain Magatama equipped to learn a skill or else it'll never be learnt. Though once a skill has been forgotten/passed on for the protagonist, it can not be gained again, so be very sure on what you choose.
The game is 3rd person, including battles, except for the overworld where you control an icon. Nocturne was what originated the press turn system, and it's the same as in SMT IV. The atmosphere is good, but the story is kinda meh. There is an alignment system of sorts based on dialogue decisions. There's a special dungeon called the Labyrinth of Amala that as you progress through it you unlock boss fights with Fiend demons to gather candelabra. It is totally optional, and completing to a certain point locks you into the True Demon ending with a special ending boss. It feels like there isn't much to say about it.
As for newcomers' traps, there's the usual stuff. There's a special skill called Pierce unlocked at the same time as the True Demon ending on the beginning Magatama that's just about necessary for that special ending boss. This game features Dante from the Devil May Cry series as a "demon" that can be used. Pay close attention to the beginning Pixie you get, and don't let her leave at the fairy place. If you keep her and bring her to this special area deep in the Labyrinth of Amala, she becomes a very powerful Pixie with really strong skills. Now it's fine for her not to be a Pixie before then through fusion and whatnot, but do not ever use her in sacrificial fusion. Even if you buy her back or something through the compendium, she won't be the same. Also for level ups Magic isn't important because for some reason the game designers decided that as you get higher leveled your magic becomes weaker without investing a lot into it. So Strength, and Endurance so you don't die as fast, is king.
As for mindset, expect frustration. Devil Survivor isn't as bad for that, but there are some escort/protect NPC missions that can try your patience (there's also some in SMT IV). It's not the bad frustration, sometimes, but it's a part of the series that these are difficult games. I've many a time died to something stupid, get upset, turn the game off, chill out, and get back into it later. Just don't let it get to you.
And for some general tips besides the demon thing:
As for what game to start with, I'd recommend Devil Survivor 1/2 or SMT IV before the others. There is SMT IV Apocalypse that came out a month ago, but it follows up on one of SMT IV's endings, and it may not necessarily be the best place to start. It's a quite good game though that fixes quite a few of IV's faults. I just listed the games most people recommend.
Also wow I've been working on this since like 9.
Tiger Mask* Mudsdale Kommo-o Vikavolt* Crabrawler/Passimian ??? Asterisks are must keeps, others are maybes, want to try and get a feel for most alolan pokemon. Low interest in Togedemaru, Bruxish, Komala, Drampa, and Comfei. No oldies/alolan forms but Alolan Muk is tempting.