Oh, my. That was rather heavy. Glad that this isn't the end, but my heart doth ache for Seed nonetheless. Glad at least that Spike didn't try to take on the Nidoking.

That said, this is an important vote, so I feel the need to take part.

Elite 4 Team:
The main 6, including a returning Rya. Kai is a pretty chill bro, but not as entertaining as Rya was. Besides, I can see him being able to handle being sidelined more easily than Rya.

Reserves
1.) Jewel; the cave system of Victory Road is glorious- it would be a travesty for a gentlewoman adventurer to not get a chance to visit it. Plus, perhaps she can become notable enough that Seed will never forget her again.
2.) Dusk; I'd like to see her become the supreme Justice Ninja that she always thought Koga was
3.) Evangeline; she really should get a chance to spend more time with the real friends that her imaginary ones entrusted her to
4-6) The Ancients. I'd like to see the Chelle/Draca plot resolved at some point, and giving Draca a little more time to figure it out seems like a good step toward that end. Chelle is just delightfully hammy. Trilo getting to see what the world is now like could be fascinating.
7.) Kai; he can take a supporting role well, and he is still a good person for helping keep Spike and Seed feeling all right.
8.) Eda; her Balboa arc must continue
9.) Missle; Pokemon activism should be spread
10.) Mellow; I'd like to see some resolution to the present inner conflict, somehow
11.) Leafe, much for the reasons that Hawkflight provided
12.) Ruto; seeing whether or not she can overcome her present worldview, or at least adapt it enough to be functional outside the lab, will be interesting.

As for level, I'd say that I'd like the team to at least be within five levels of Beau's 'mons. So, around 55-60? Within at most ten levels for the reservists.