@Winter To be honest, I wouldn't say it's a good idea to leave details about the antagonists ill-defined prior to the roleplay, especially since the main objective is to defeat them. I'd think, from a game master perspective, having those ironed out beforehand, even if not enumerated for potential players, would be inestimably useful for predicting what sort of events the cast would face or sorts of obstacles they may have to overcome; the actual RP would be better organized as a result. And it should be noted that, even if the general public understands very little about the Natural Order, there are no real restrictions set in place on Hourglass recruits, so the amount a character claims to know is essentially up to their player, right?

As for your second answer, the amount of Pokemon a character owns is up to, essentially, who they are. That's what I meant by "dependent on background"; a rich boy from Kanto would likely have different Pokemon than a waitress with a five-to-nine gig who's lived in Hau'oli her entire life, similarly to a young man who's made a living out of rescuing Pokemon would have a different party than someone who hasn't. I'll also presume that, because of what you brought up about Trainers in the game, the culture of Alola is exactly that: lax, laid-back, just like a tropical island paradise. Of course, that atmosphere could be perturbed by the construction of the League, drawing in more competitive Pokemon Trainers from neighboring regions.

But, going back to the detail about Pokemon ownership, I'll note that I'd feel uncomfortable not describing my own character's connection with their partners in their bio section, just to "justify" things, in a sense. At the same time, I'm also not fond of giving my character a full team from the get-go. It's a preference thing, really; I suppose I just like treating each Pokemon like its own little character and having six makes that overwhelming to do. That's essentially why I asked the second question, and also because I wanted to see how much world-building you'd already done. Wouldn't want to create inconsistency if I end up writing an app.

I should also be the person—as if I'm not "that person" already, aha—to bring up battle mechanics. How will battling and move usage translate to this RP? Things like dodging, the amount of moves a Pokemon can use, etc.

And Trial Captains, in some form, are permitted. Okay! It's something I'll keep in mind but I probably wouldn't head that direction myself. It really depends.