-orbs can be changed in the settings, they are either friends only or 'everyone,' which I imagine is a sampling of random people
-i just did the same old 'invite to game.' he can't hurt allies unless I turn off the safeguard in the RB wheel, and I can kick him any time. When he joins he sets up his character and I get to decide what percentage of EXP and gold he gets to take. annoyingly, he even got 50% of my rent and owned shops, not just treasure chests. but then when he dropped out, i got all his gold back in one lump sum and he didn't get any in his pocket on his side. He thinks he might have quit the wrong way or something.
-it only takes a second for them to hop in or drop out, probably even better than SR2.
Camera is not perfect, it's completely computer controlled. it works well for combat and walking around but if you're going up a spiral staircase or behind bushes to get to a chest it can be annoying. you get special bonuses for doing combo attacks, and if either player holds RT both of you will get the experience orbs, you get into a nice rhythm with that.