For example, I write for the FF8 fandom and Squall Leonhart is present there as well as in the Dissidia Final Fantasy universe (along with a handful of other main protags and antagonists) and Kingdom Hearts (much older than both. Would it be acceptable to use two different versions of this character (and other characters that have different versions of themselves) but obviously pair them with the people present in that universe?

I'm a little unclear on this paragraph so bear with me, but:

If these are separate/different versions of the same character in each different fandom, then, yes, they would count as a new canonical character each time, as long as that's how you and the fandom(s) in question regards them. (Which I think is what you were asking?)

If these characters appear in different fandoms as the same character, then they count as the one canonical character here, too. You can of course use them in all the fandoms they appear in with anyone you like; just not in a repeat pairing. (Multiverse and crossover pairings are very welcome here!)


As to specific fandom quirks & issues - that really is up to you as to how you (and/or the fandom) would usually treat those characters. If that's as separate characters (which is what it sounds like here) then, yes, absolutely, treat them in the same way for this challenge. And if not, then not.

I hope that helps.