i'll at least keep an eye on it
here's the ultimecia one
http://www.ff8a.com/ulty.html
it's longer and there's more kinda pointless text, but it's broken up into sections, so you can read only the things that look interesting, or bit by bit, whatev
i have three problems with rinoa = ultimecia:
first, a sorceress must pass on their power. since rinoa is the last sorceress, that means ultimecia is obviously connected to rinoa, even if only marginally so. but the probability that rinoa is sealed then reawakens and becomes ultimecia is, at best, equal to the probability that rinoa just passes along her powers to somebody else, who passes theirs on to somebody else, and so on, until one becomes ultimecia.
second, the theory itself asserts that rinoa is not hated by the world for being a sorceress despite her fears (although this could just be foreshadowing), yet the theory relies upon the assumption that rinoa will be hated by the world in the future after reawakening
and third, the theory also recognizes that a sorceress without a knight will lose their sanity, but squall would be dead by the time rinoa reawakens and the theory makes no mention of a new knight. an insane sorceress could still have the same catastrophic effect on the world that ultimecia had in the future, but ultimecia is still sane when her consciousness travels to the past (ff8's present)
i think she's just some random future-*****
