Because Rinoa's final thoughts are about Squall? I'm with KaiserDragon here, this whole scene is simply just Rinoa thinking about Squall, the Ring is a symbol of Squall, she even is talking about Squall after her life support goes out, and when Squall is time jumping through Rinoa's memories, he winds up in her body at this time and encourages her to live. That's when she wakes up and sees the necklace, after Squall has been encouraging, her, I feel this pretty much shows that the necklace is meant to be symbolizing Squall, not just an arbitrary plot device that the game never goes into, but supposedly is connected to a major plot twist that neither source materials support, and is so subtly hidden in the plot that it takes careful interpretations of the scene to realize what is "really going on".
It's not arbitrary source material. You get to name the summon earlier than that. It also wouldn't technically be a plot device either. GFs were established since the beginning of disc 1. Having one save Rinoa in outerspace is far more consistent then a dues ex machina in which she can somehow breathe in outside space because she's being instilled with hope.

She never comments on her feelings about Adel's memories, she simply stated she was in her younger body, before Ellone ejected her. I've already quoted the only thing she said about Adel above. The big issues with the theory, is that we have to assume Rinoa spent a significant amount of time in Adel's past to mistake them for her own memory, but the game kind of shows that the time traveler and their body experiences the past in the same amount of time. Whenever Squall and Zell are knocked out from time travel, they remain that way until whatever in the past is resolved, and comments from other party members suggest this is a significant amount of time. Whereas, Rinoa was briefly in Adel's past before Ellone pulled the plug. Hardly enough time for any significant amount of memories to be assimilated in Rinoa's body.
I'm afraid you're mistaken on a few things here. First, Ellone had nothing to do with the ejection. In fact, she wasn't even there until afterwards so they could properly send the party into time compression after Ultimecia. Rinoa was forcibly put into Adel's past by Adel herself. Rinoa obviously looks into Adel's memories for an indefinite amount of time during a fight between Adel and Squall's party. Squall's party is forced to go easy otherwise Rinoa will die. Also, Rinoa was obviously not consciously active during the fight otherwise she most likely would've said more than just "aaah!".

Also, take a look at just how Rinoa is junctioned. There is an obvious Cross-symbolism in the way she's junctioned unto Adel. Typically, the cross is a symbol of suffering or eventual death. Rinoa doesn't suffer or die because of Adel so why was that symbolism there? Unless... she eventually did? I also find it a bit curious that the music being played when Edea's powers are transferred to her and when Adel junctions her was 'A Sacrifice'.

There is also the argument that this requires years of being in contact with Greiver to eventually wipe out her memories so she can confuse Adel's with hers. This still requires that you assume that Adel's memories are not targeted by the GF, which, without any really direct evidence to state contrary, is a bit far fetched.
It's not at all. Rinoa never took off the Griever ring, why would she? It's a symbol of her and Squall's love. That we can agree on. Again, I stated before, it would logically target her earliest memories (as shown by the entire orphanage twist in disc 2),and Adel's memories wouldn't be her earliest. It would be her own childhood that was targeted first.

The other issue here, is that Ultimecia is stated to exist in a future several generations from their own time, which means she's at least 60 to 90 years into the future, but the Ultimania, specifically states that Witches have normal human lifespans. So now we have to find evidence that explains how Rinoa could live that long to become Ultimecia.
Not to be insulting but I believe it is you who are making indefinite conclusions based off inconclusive proof. I apologize if that comes off as rude but I don't like being accused of doing something and then see the accusor do the same actions themselves. We're never told how far into the future Ultimecia exists. Even if it was 60 to 90 years, it honestly doesn't make it impossible to be Rinoa. There have been rulers of ancient civilizations that started out at the ripe young age of 81 and this was during the time the life expectancy limit was 35.


Actually, she isn't equipped with any GFs for the portion of the story she is incapacitated. If she had them, she would've used them to rescue herself regardless. Her sorceress powers aren't ever focused on unless she's being controlled. Don't you find it even the least bit curious that after her oxygen ran out, the only thing emphsized was Squall's ring?

Finally, I'm not sure what you mean by 'the persons being' part. People grow into whom they are based on their experiences in the past. If her earliest memories faded away and all that was left was Adel's then all she could draw from would be Adel's memories.

I'm not entirely sure what could've happened to those memories. It's not implausible that the year long decades eventually wiped them entirely and left her with only Adel's memories.
Actually the scene leading up to Rinoa seeing the ring, is Squall's consciousness in her body, encouraging her to not give up. I also would like to think that if Griever saved her, the game would have made it more obvious with a flash of light or something. I think this is just a matter of willpower. Even with her oxygen gone, it would still takes anywhere from 6-8 minutes minutes for the lack of oxygen to irreversibly damage her organs and kill her. Losing consciousness would take less time and I feel Squall's encouragement simply kept her from doing so.
Ah, but the game is known for subtle hints. Good ones too. Look at the orphanage cut scene, Irvine's actions after first meeting him were subtle hints about it. Most people didn't even catch that, which was why the orphanage scene 'came out of nowhere'. There were other little things too, Cid giving Squall the commander position and Squall's short comment 'don't act like you've decided this since my childhood' hinting at an event in the ending, the President of Esthar's actions in space hinting that it was Laguna, the 'silent man' showing up after Squall saves Rinoa from the chamber and allowing them to escape being Ward, etc.

The point is, subtlety was a definite strong suit in Final Fantasy 8. It had a lot of it and it was done quite well.

Her fondness from Seifer stems from Seifer's dream to be a Knight that protects a Sorceress. He's just easily manipulated because of this, as well as him apparently recognizing who Matron was from the start. As for the scene where she asks Squall who he is, they are both occupying Rinoa's body at this time. It stand to reason, she simply felt Squall's consciousness enter Rinoa's body and was simply trying o figure out who this other consciousness was. Her reaction is really not far fetch.
A valid point. I suppose I saw the scene differently. I assumed Ultimecia could 'see' Squall just as Squall saw her but perhaps I'm mistaken about that...

Using Scan on Griever suggests that Griever is simply born from Squall's interpretation of what he feels the Ultimate Summon is. The party kicked her ass, they finally kicked Griever's ass, why not Junction to him and see how they fare with their combined power?

I just don't think their is enough evidence to suggest R=U, on the contrary, I feel there is more evidence to suggest Ultimecia is simply what she appears to be, a psycho, power hungry witch from the future.
But why Squall's mind and don't you find it odd that she uses the same strategy Adel used? Junctioning with something else to make yourself stronger. Why not create more GFs like the ones you fight before you get to her? Why junction herself unto a monster that Squall has a fondness for?

And, actually, regardless of if she's Rinoa's future self or not, she's still a power-hungry psycho witch from the future.