In general, the special guests tend to be pretty approachable, and are usually happy to sign something and chat briefly. Just be aware of the situation- don't hit someone up for an autograph as they are entering the restroom, eating or in the midst of a game. Otherwise, if you see them walking around the convention area, just ask if they have a moment to sign something. Be polite and odds are you will be able to come away with an autograph and maybe a question or two answered as well. Having said that, remember that they are all human. Maybe they aren't feeling well or have a commitment they are going to that prevents them from signing right then. They will most likely be around all weekend, so you will have another opportunity at a later time.
As far as your question about the game on Friday being viewable, the games are played in rooms with multiple events happening concurrently. There is no "private room" where official games are held so there is the opportunity to stand near the table and watch. Just be mindful of the fact that sometimes there isn't much room around the tables and you can prevent people from getting through if you stand in the wrong spot. As long as you aren't disruptive or do anything to distract the people in the game, I would think anyone would be fine with you watching the game. I have done that myself a few times, taking some time to check out a game I was unfamiliar with or that just sounded really interesting but didn't fit into my schedule. On the other hand, maybe Chris Perkins travels with his own security team to keep people from spectating as he runs his games.
Obviously, I guarantee nothing and since I am not part of the Gamehole Con staff, if I am giving you incorrect information I am sure someone who is will be quick to correct me.