If Ultimecia were, say Rinoa, and she was so twisted by insanity, AND has used GFs a long time, it's perfectly plausible that she could forget her past, even what she used to look like.Now, none of the people in the game's present - Rinoa, Julia, ect, have any problem existing the the world at its current state. In fact, were Ulty to succeed, they would all be destroyed (Including Julia if the game lied and she were still alive).
So in essence, because EVERYONE but Sorceress Ulty would be destroyed during Time Compression, the paradox twist works for ANY character, living or dead, past or future, NOT just Rinoa. Granted, the game ends if you are KO'd, but its enough that Ulty should not even TRY to kill herself. Therefore, because she attempts to compress time, an act which would kill all characters other than herself, Ulty CANNOT be anyone other than Ulty.
I mean, Squall forgot his entire childhood after a few years of GF usage, and since Ultimecia lives "many generations" into the future, even if she'd only used GFs for a third of that time, it'd be enough to, coupled with ther insanity, make sure she had no memories of the past.
Moving on, THERE IS NO CYCLE.
Ellone says the past can't change. Assuming she isn't lying(which seems ridiculous), that means what it means.
If the past can't change, the only loop you'd get would be if you decided to stay with little Squall when Ultimecia gives her powers to Edea, but that's merely the kind of "loop" you get when watching a video over and over again(if that is the kind of loop you're talking about, then forget this).
Ultimecia dies, and that's that.
Ultimecia MAY go back to the past in order to try and change her destiny, but she can't, because time won't change.
http://www.slimits.com/ultimecia.html
Something I wrote on Rinoa being Ultimecia. Also includes a rather long bit on Time Loops and the likes.
