I'm not so sure about the 'Hulk clap'. If you check out 1977's 'Superman Vs. Muhammad Ali' Superman employs that exact same move and I'm pretty sure he was using it before then.
Sure, but the move is more associated with the Hulk, and given how many other overt Marvel nods there were, it's not unreasonable to suspect that this was intended as another one.
And of course there was the whole 'Spider-Man' talk between Jax & Stein in Jitters in episode one.
Yes, I did mention that exchange, right after I mentioned the Hulk clap.