Oh, hi, headcanon!
This has been my headcanon for a long time, actually. It makes sense, because honestly, Feferi would have NO reason to want/believe in a troll society that was peaceful, without the caste system, unless she had done it before, even if she didn’t remember. It’s true that it was mostly her Lusus’ whispers, but even then, Feferi could have simply not believed it. Her breeding would show that she should be as violent as the Condesce, but she is not. (Unless Hussie is keeping her hidden in his back pocket as crouching cutie, HIDDEN BITCHTITS, which is entirely possible.)
Her beliefs, while influenced by the current world. (Culling for her lusus, etc,) it’s stated she regrets them, but does so out of necessity. And, all her plans line up with the Sufferer’s words of the old world. So… yes. I will believe this forever until canon disproves it. (Which it probably will.)
I also believe, headcanonheadcanonheadcanonfanficheadcanon that if this were true- the first Feferi was killed by the Condesce to usurp her, and that it was in Feferi’s fate to usurp the Condesce the same way.
And then I wanted to write more Feferi-as-Her-Imperial-Radiance again. dammit Empress Feffles I love you.