Looking for confirmation this is an AT-12 (2 seat version of the P-35)

[GreenKnight121]

In the photo of the AT-12 flying, that wing looks very much like the P-47 wing. It's actually a pretty cool looking airplane.

I don't have proof, but I think the wing was an incremental design step in between the P-35 and the P-43

Yes, the AT-12 wing was modified from the P-35 wing - and was similar to the P-43 Lancer's wing - the P-43 looks much like a smaller P-47 with nose guns.

The attached images are from the Squadron/Signal Mini book on the P-35: