conhecer means "to have knowledge", so it applies to movies, albums, actors, etc. Here, conhecer and saber work!

For me that's correct too (although I think they'd prefer "disto" for the translation).

no, because then you should have left "nada" out.

yes, anything in negative sentences means nada

"I know nothing beyond that" would (or should) be another valid translation, so "nada" could mean either "anything" or "nothing" depending on how it's phrased in English, with the same end result.