dunno about the other categories, but comedian - surely lenny bruce gets a mention. The few rarer bits I've heard of him that wouldn't have gotten within a mile of commercial media of the time are pretty decent, and he certainly embodied the idea that freedom of speech was paramount to any society.
Athlete - sort of - Yossef Gutfreund - I believe he was at the munich olympics as a wrestling referee/judge, not sure if he had a competitive background - but he gave his life blocking the door with his body against terrorists yelling and raising the alarm and was definitely the reason some of the Israeli athletes escaped and lived. People talk a lot of shit, but when you're faced with heavily armed aggressors and completely unarmed not everyone would man up like that. Some would cower, some would run, some would stay silent. He fought, he made noise, attracting more attention from the terrorists and had to know he was going to die doing that, and did it anyway. To me that's more telling than any opinion I or anyone else might have about Israel, international politics and all that. He was put to the test, and he stood his ground.