The captured Zero was important in the refinement of tactics, it provided no direct
input into the Hellcat design. The contract firmly fixing the Hellcat configuration was
signed six months prior to the crash of the Aleutian Zero. (imo the Zero was a rip off
of the Gloster F.5/34)
As for the F8F being influenced by the FW190. I've heard i before but no one can point
out what the supposed influences were. The F8F looks like a meaner,leaner bubble topped
F6F. I personally see no resemblance to the 190 at all.