Uh-oh, someone just dug up my favorite thing to think about in the whole series.
On topic: I don't think The One was a way to start over, I think it was a way to continue the series, if she ever decided to. (Though, that includes starting over if you include the numerous trump cards she put into the series, such as sario-rips, the Ellimist, etc.)
TLDR version: I think that The One was mentioned in 26, 41, and the last book. (Was it ever explicitly stated by KAA that The One was a new character that was never mentioned before?)
You're on crack what's your reasoning version:
In 26, the Ellimist makes reference to the Yeerks being a pawn in Crayak's plan, and then leading the creatures they take over to a force that is even more controlling. "<Earth is part of our game, Crayak's and mine. He would have the Yeerks absorb humans and later be absorbed by some still more vicious species. But Earth is not the reason I have come to you now.>"
It is part of the Crayak's vision to have the galaxy controlled by one strong race, as stated by the Ellimist in 26: "He wants a galaxy cleansed of creation. His goal, I soon realized, is to destroy life. His method is to use one species against another, strong destroying weak, and then strong in turn being destroyed by the stronger still. He believes that there should be only one species. A single sentient race, which would be subjugated by him."
Most would think that means one Master Race that would kill all the other races and be under the control of the Crayak. But, if the Crayak were smart, he could instead control one being that could assimilate all the other races (The One,) and then use the assimilated beings against the rest of the universe, and then he has his one Master Race under his control, which is basically all the races in the galaxy under his command, then he could go back and b!tch-slap the guy that kicked him out of the other universe with his massive army of everything.
Now, as for 41, I do think it was "The One" that was looking into Jake's mind. My guess was that it was actually just a dream brought about his own paranoia/stress about the situation he was in, but I think that Crayak was always able to look into Jake's mind, not only because of the Yeerk dying in his mind, but because he morphed a Howler, which had a hive mind of sorts and was controlled by the Crayak. If The One was a pawn of Crayak, that would mean Crayak could probably give a sneak peek into Jake's mind, which would prompt him/it/them also being able to be heard by Jake. I think the description of the voice, which basically seems to suggest a unified mind of assimilated victims, is enough to surmise that it could be all the creatures that The One assimilated. And it makes sense that The One would say things like "they bear studying" because the entity most likely had no contact with humans until right then.
And as an off-topic to my off-topic, I don't know why everyone assumes Jake chose Cassie, at the end of the book I always assumed Jake DIDN'T choose Cassie, which is reflected at the end of the series when their relationship began to fall apart because he began to finally think about the rest of the world and saving it instead of what Cassie wanted.
Anyway, I think that all opens up the ending for basically an Animorphs 2.0, where it is essentially a war between The One (Crayak himself, in a sense) and the rest of the world. But I'll save my Kelbrid/Andalite/rest of the universe theories for later because everyone is probably reading this and going "you're crazy" right about now.
Feel free to poke holes in the logic, better now than after I post fanfics and everyone goes "LOL PLOTHOLE!"
