Surely Quinto is a more obvious choice for the Sub-Mariner, given Namor's oft-remarked resemblance to Mr Spock?
I see Namor as more conventionally-handsome than Spock (never thought about a Namor-Spock connection). Quinto would be more the Doctor Strange type. And he's vanished because he's on Broadway now, which annoys me, he needs to get his fine ass back on TV!
Of the other suggestions, Patrick Dempsey is a good one for Doctor Strange.