My understanding is that Goodman said to Stan something like, "Donenfeld has this Justice League of America book which seems to be doing well. Let's try a super-hero team book." And then that was the extent of his contribution to its creation with the following possible exception. Goodman told people that what Stan and Jack came up with was called The Fabulous Four and he suggested the change to "Fantastic." Stan and Jack both denied that.

So the answer to your #1 is no. #2 is a probable no. Goodman clearly saw The Hulk as more of an attempt to do a Frankenstein comic...and the Thing of course was part of a hero book.

Jack and Sol Brodsky both claimed (though Stan said it was not so) that Stan's initial idea, when Goodman asked for a hero book, was to revive Captain America, Sub-Mariner, Human Torch, etc., and that Jack suggested that new characters would be preferable. If this is so, then (the theory goes) that the inclusion of a new Torch was kind of a compromise on the abandonment of that concept. But they always figured that if the new book clicked, they'd eventually bring back the star characters of yore and after that, it was just a matter of figuring out the best place to do so. The delay on Captain America was, in part, because Goodman was afraid of a legal challenge from Joe Simon. Finally though, when he saw super-heroes catching on, he decided to take the risk.

With Ant Man, what seems to have happened was that Goodman liked the book and thought it was commercial, especially in light of DC's encouraging sales of Atom. At one point, Goodman wanted a team book of insect-themed heroes including Ant Man, Spider-Man and a character Stan began developing but abandoned called Bee Man...no relation to the one Joe Simon later did. I don't know that the idea of reviving The Whizzer ever occurred to them...but the point with Ant Man was that they'd already launched the idea. They didn't invent Ant Man because of the Atom. They just decided to keep him going.

As for #5: Goodman knew there were problems. He had to get any new book approved by Jack Leibowitz at DC, and Liebowitz didn't want direct competition. So to a large extent, the answer is yes.