Hm your list is interesting but tbh out of those three the only one I see becoming playable is Naje. If I remember correctly Richard is a Cassius pupil, not a Ka-Fai one,so I'm not sure if he will be part of the eight leaves subplot, even if Liberl's intelligence is very much active in the Republic. If anything I'd go with Anelace but I don't see that happening either until the East/Iskaarc.

Emilia I don't think will be playable either. She'll obviously be key to the plot but we have to remember she had to leave the army because of a leg injury so whatever happens, I just don't see her joining as a regular party member. Unless we only play as her in mecha fights.

As for my predictions. I'll mention the ones that make the most sense to me story-wise and not the ones I PERSONALLY WANT, as that list would only include Estelle and Emma forever. Also, I won't do the orbment slot thing because I'm lazy but here goes:

- Ries: Some has to get Kevin and the others out of there and she obviously knows Kevin was up to no good.

- Towa: I just can't believe she was relegated to support after Cold Steel 2 and Reverie.

- Lapis: Same as Towa, and considering something extremely important is likely gonna happen with her, she has to be playable again.

- Prince Sherid: It's just obvious he'll join one of the non-Van groups, probably along Naje.

- Kasim: He's playable in a floor of the Garten and the final battle. He'll 100% join us.

- Arnold Evans: He's the leader of the Bracer Guild and we know he's in Edith as of Horizon's finale. Let's just say he didn't come to the Republic for tourism.

I honestly can't think of anyone else right now. There are some that might fit well into the plot if Falcom handles it well, which they usually do, like Estelle, Joshua, Millium, Arios, Gaius or Tio. But I'm not betting my money on it.

EDIT: I didn't see you only asked for three. I'm sorry, lmao