Yeah, don't bug him too much if you can help it.
I'm really not sure. Mine don't look like that before they shed, so I'm thinking it may be something else. The only snake I've seen look like this was a little one that just wouldn't eat for a while and was losing weight (she's ok now, don't worry, I figured it out), so that's why I'm wondering if he's too skinny. On a mostly unrelated note, how often are you feeding him?
Yes, that's normal. They save up their poop and they let it loose on the day you have zero time to clean.