Caius the Bigger

I think that all the appearances by the 70's characters are just there to screw with the Avengers even further and destabilize their already shaky trust. I don't think that this Secret Invasion goes back that far. If you think about it, the Skrulls didn't decide to get serious until after the Kree-Skrull War. And then they'd take even more time to apply what they learned from the Illuminati's capture to their infiltration units. So I really think they're all Skrulls.