Greg responds...

I don't think I was mum. The Fantastic Four were active, but dealing with threats on a much larger scale. Ant-Man was active but was very much under the radar. The Hulk was jumping around the American Southwest, more legend than anything. Professor X had just opened his school, but only had two students so far, Scott and Hank.

Thor didn't have his hammer back yet. Tony Stark had not yet been injured. Namor was still a bum. Captain America was still frozen. (I felt that Uncle Ben had a big collection of World War II Captain America memorabilia in the attic, which in part inspired Peter to put on a costume in the first place.)

Had we been given our druthers, we definitely had planned to have a Human Torch guest appearance. (Always loved the Johnny/Pete dynamic.) And eventually some of the others. Though, as I stated before, we never planned to make it a Marvel Team-Up show. Maybe one big guest star per season.