Originally Posted by
Sir Bahamut
I'm perfectly aware of the contents of the Ultimania, which you don't seem to be yourself. The Ultimania doesn't explicitly state that Rinoa will die before Ultimecia is born. It says that a sorceress lifespan is that of a regular human beings. All this proves 100% is that Rinoa couldn't have lived to Ultimecia's era through natural means alone, but the game itself provides a way to get around this, namely the Sorceress Memorial seal. Rinoa could have, in theory, been sealed down, driven mad, and woken up in the future as essentially Ultimecia.
The only problem with this theory is that it is not hinted at by anything in the game or in the Ultimania. There's just given no reason whatsoever to assume that this is going to happen, which is why I said the most damning evidence is the lack of evidence, because that's what the Ultimania basically did. It wasn't really about it disproving the theory on a technical level full stop, it was about disproving the only thing which could have allowed Rinoa to become Ultimecia without any extra assumptions.