Mujuju

Silas can use lances from the start, and if u marry him to azura, he can eventually go into falco, where later chapters love fliers. He will then be a fast, hard hitting falco user and rally speed is really useful for later chapters to reach OHKO benchmarks.

I disagree with Setsuna being the best mom for Selkie, probably mediocre at best. She passes down archer line with the only skill that's really notably useful is Prescient Victory (+4 damage when initiating battle). Her speed is already great, any more is overkill, and there's not really any merit in specializing in it since she will double nearly all enemies anyways. I'd say she benefits way more with Kagerou, Oboro, or Hinoka. Kagerou really patches up her offense while giving her a great class tree, and you can do some sheninigans with four fangs + snake venoms, along with copycat. Oboro gives great all around modifiers and growths, and allows for nasty enemy phase combos (four fangs + speed + defense seal). Hinoka is just all around great for Selkie.

For the conquest route, she can be quite useful as she is the only unit with the archer tree line. She will have one of the highest hit rates in your army since hit rates can be very shaky in this route, especially later ninja chapters (Bows>shurikens). If you baby her in her recruitment chapter, you can get her to lvl 8-10 by taking potshots, and increase her bow rank to D or C.

Selena (and Odin/Laswald) are unique in that they get Hoshido classes in their class sets. She comes early enough that you can raise her bronze lance ranks, and can build buddy support with Camilla/Belka really easily as both of them benefit her w/ pair ups. I always go Pegasus for her, then end up at Wyern Lord. As others have said, bowknight just doesen't quite cut it for her.

Yes you can, just did it a few minutes ago. Seems like you can reclass into the dlc classes which are not released yet, such as witch, lodestar, etc.

Yes, you can change the difficulty to rush it as well.

Takumi wants more speed, and makes the most out of it with a Hana pair up. His son definitely appreciates the speed as well. Oboro does just fine for Takumi since lancer gives speed in pair up as well, just not as much as Hana. His personal bow is OP anyways, so it doesn't really matter. Kiragi definitely suffers much more since his low speed and not having a Takumi's OP bow do not complement well with each other.

Well, it's Ryuoma that's going ham. It does help if Kaze gets 1 speed which allows him to double the Mercs in the next chapter. I think getting 2 str on him allows him to one round the mages next chapter with Rinka pair-up. My numbers might be slightly off. It doesen't matter if Sakura or Hinoka die, they will only retreat. However, talking to Hinoka gives you Concotion which is extremely useful in Lunatic.

What are the stat bonuses to weapon ranks?

Anyone can become a Dark Flier. Only females can become Great Lords, only males can become Lodestar.

You have Mozu's chapter to easily pick up weapon ranks if it bothers you too much.

I don't play for LTC, but when the overleveled royals/Corrinsexuals earn 1 exp during the join chapter(s), I see it as wasted experience that some other units could badly use. For early ninja reclassing how well does he do losing his sword access, as well as the fair share of axe/bow users in the early chapters?

I believe the other two are Reverse God and a Spirit Dust.

Well, Orochi does kill her speed a bit, but she is the only mother besides Kamui who can pass down Ogre Strike for some Ophelia crit sheninigans.

No, it does not add the marriage class to the reclass list. If you want to reclass to spouse's class pool again, you need to use another marriage seal. Doesn't matter too much since they cost the same, unless you pick up a free seal.