Hank Pym(Antman/GiantMan)--Joel Edgerton
I personally think he looks like Hank(minus the hair), and think he has the chops to play him. If you dont think he can be a lead actor, I'd stop what you're doing and watch "Warrior".
Janet Van Dyne(Wasp)--Anne Hathaway
With her stellar performance in TDKR, and now with that franchise (possibly) over, she'd be perfect in this role. She could not only get the action vibe, but could also pull of the entire look of Wasp.
Scott Lang(2nd AntMan)--Jensen Ackles
I know this pick is ripped off from ScreenRant, as is the Joel Edgerton pick, but he is the spitting image of Scott Lang. And for those wondering why I'm picking an actor for Lang, it is rumored he will appear in the first movie.
VILLIANS
The Living Laser--Alexander Skarsgard
He'd be the perfect choice for a starting villain to get this more science-based comic book movie, and I think this actor can pull him off. I chose him so they could go with the story of him developing a stalker-ish love for Wasp/Janet, then him kidnapping her. I think he can pull of the kind-of reclusive scientit type. Also this pick is based off of if the did the Living Laser costume, not the electric-only look.
I'm not gonna cast anyone else, until there's more info on this movie released. I hope you guys liked this, as this is my first post on this site. Feel Free to voice your opinions in the cmments!