CallMeTheDoctor
Super Freak
Namor is in a grey area, I believe universal and Marvel have the rights to him.
I don't see how Hulk being in Atlantis makes much sense, if any at all. Can he even breathe underwater? What kind of conversation can an angry, arrogant, irrational Namor make with an angry irrational Hulk that can barely articulate any words on the surface let alone in water have?
I'd love to see Namor show up though, if they can find a decent way of explaining Namor showing up in the MCU I'll be happy.
My guess is that Banner is floating at sea after the crash. Gets abducted by Namor, and while imprisoned; he turns into the Hulk. Namor is intrigued by this, and Banner of any tech from Atlantis; becomes a mutual thing. Banner can be off the radar, and I'm certain Namor would get some form of benefit.
It is quite possible, just don't know if Marvel would go that route.