No, Superman has conventionally been shown as a white character in the comic universe. There haven't been any significant storylines where he was portrayed as black.
Not that I know of. Usually, comic characters have a certain level of popularity or recognition, but I haven't heard of Patience Phillips being in the comics. It's possible she's in some obscure or niche comics that aren't widely known.
No way. Aquaman is a DC Comics staple. The two comic universes, DC and Marvel, are separate, and Aquaman remains firmly within the DC realm and has never crossed over into Marvel.