FFVIII Rinoa/Ultimecia Theory

I know this was mentioned on FF Union several months ago, but I don't believe you guys ever brought it up previously. There's a pretty big theory out there (that sort of ties into the Time paradox theory also posted) that Ultimecia is actually a future version of Rinoa. There's a whole bunch of reasons why people believe this and I won't go into all of them, but there are several worth mentioning. For one thing, Squall gives Rinoa his Griever ring at some point in the game (I think maybe Zell was supposed to make a replica of it for Rinoa too, I can't remember for sure), and Ultimecia later uses Griever as her GF in the final battle. Rinoa was also the only living sorceress by the end of FFVIII (except for future Ultimecia) and as far as I know, a new sorceress only comes to be by an old one passing their powers to her. The last (and weakest in my opinion) support that I can remember is their faces in FMV look very similar. Honestly I think it's because it's a PS1 game and would make more sense to just edit one face to make another. I don't think they created them so similarly for any other reason than cost.
Overall I think it's one of those theories that probably isn't true. Ultimecia seemed almost Necron-ish in that there really was a pretty poor explanation of what her motives were and why (even though FFVIII is probably my favorite FF), but I don't think the creators were implying that Rinoa becomes Ultimecia. 
If you already covered this then I apologize, but if not then there's a whole lot more information online than what I covered if you're interested.