No.
Epic React: Full React
Peg Turbo: ZoomX on top of React
Zoom Fly Flyknit: React with the same carbon fiber plate as the Vaporfly
Vaporfly: ZoomX w/ carbon fiber plate
Maybe the side of the foot more adequately disburses the pressure of the lacing? IDK, I'm making stuff up, but it could be important for actually elite runners.
The ZFFK has the same carbon fiber plate that the Vaporfly has.
Compared to the peg turbo... it's hard to say. They don't feel similar at all. Peg Turbo feels like a softer Peg 35. I terms of slow -> fast runs, I'd probably say Epic React -> Peg Turbo -> Zoom Fly Flyknit -> Vaporfly.
Yep. Unless you have a weird shaped foot (i.e. thick at the toes) or bought your VF1s snug, the VFFK is the same exact shoe. It's just that the flyknit is tighter than the VF1's engineered mesh.
I keep seeing this here, and I don't agree with it at all. If you line up the back of the actual heel of the shoe rather than the midsole, it looks like this.