1. He credits Martin Freeman for his comedy chops.
2. For Halloween, he wants to be the Invisible Man.
3. Yes, he's read the letter Julian Assange wrote criticizing both The Fifth Estate and Benedict's performance.
4. He'd be cool with endorsing a line of pants (British slang for underwear) called "Cumberbritches."
5. He's joined Tom Hiddleston and Matt Smith in creating elaborate crossover fan fiction.
He was probably kidding, but every Sherlock/Loki/Doctor tumblr read his comments and died happy.