There's literally nothing wrong with what you're complaining about, but I'll try to keep this as composed as possible.
Aptitude only boosts the chance of gaining a stat point upon level up. (+10% to all growths). The Warp skill is legitimately obtained in the Witch's Trial DLC, meaning it's perfectly legal for every unit to have the Warp skill. You can get the Iote's Shield, Point Blank, Paragon, (stat)taker skills, etc through the DLC that was just released in Japan. While it isn't released in America officially, you can still access it by injecting your save into a Japanese copy and playing it on there. You would then be able to inject it back, retaining everything you've obtained. The Pebble dagger, Vanguard's Brand, Exalt's Brand, Fell Brand, and Hero's Brand and any skill scroll are in the DLC's data and will be removed from your save upon loading the file back up again. In the case of movement, each unit can legitimately have +2 permanent MOV from Boots. It's perfectly legitimate and possible to get +7 of any normal weapon that isn't a "legendary" weapon through the Museum Melee DLC, it's just rather tedious to the point where most decide against it. While it's illegal to have all characters receive all stats to around 70, it's still possible to boost every unit's stat caps through building statues in My Castle. Anna remains recruited if recruited in the Japanese DLC and injected back into an American copy. There's a similar post about it, but having anything outright "illegal" will get you blacklisted and softbanned from using online features. Examples would be having everyone as the Hoshido or Nohr Noble classes and using more than two Kitsune or Wolfskin units.
I hope this answered any questions and helped you reach a better understanding of what's considered legal/illegal.