I really think Ant-Man is going to be crucial to this film. You do not break up a sequence *very serious feelings* with a kind of humourous piece at the end unless that guy is somebody important. Like, Marvel and Hulk will come to fight Thanos. Ant-Man comes to defeat him.
How did Scot get out of the Quantum Realm?
That I think is your answer - if we find out how Scot managed to escape without help (apparently), then we will know exactly how he helps to save the Multiverse
I guess we'll just have to buy a tkt come March & find out, now won't we?
How do you arrive at the conclusion that he had no help from a few second shot of him ringing the Avengers doorbell?
This is a comic book put on screen, any # of possibilities exist....
Oh? Which is which?
As it should. I am not a fan of trailers that give you the entire movie. Trailers should be an amuse-bouche - giving flavor, whetting the appetite, but not substantive.
Of course, it only takes a generation for the universe's population to double again. Thanos has only set it back by a few years.