I have an idea that happened to inspire me before I have the best grasp on this, and it's for a main vocal after the fact. Two delay taps with no feedback, detune one +5 cents panned hard left, the other -5 cents, panned hard right. Not long delays at all, a few milliseconds. That's a starting point.
If that's doable and it worked, I'd try modulating the formants.
I'm just trying to learn the fundamental building blocks before going crazy with this
Is it doable?