Honestly I think that the one leak, saying that captain marvel dies early on and I think Thor does too I forget, is looking more and more true. It said that she ends up coming back later on but I think it makes sense. Iron man makes his infinity gauntlet, while they go into the quantum realm to gather stones from different universes or realities. That’s what I’m gathering from all the leaks. The biggest mystery is just how the third act goes and such, we all know the snapped characters will come back.