If things turn out badly, you could try making a bet with your roommates to trick them into sleeping with a large bath towel firmly wrapped around their heads. Blocks out some noise and most if not all light. Or bring sets of earplugs and sleeping masks as gifts the first day as a preemptive strike against possible conflict.
I'm actually planning on bringing this little box of a hundred earplugs. They can certainly have some, but I worry a little bit about whether or not they will hear their alarms.
I started using earplugs about a year ago. (Just one, on the side of my head that's not on the pillow.) I have trouble falling asleep when there's noise or light, having grown up in rural New Hampshire where there is near total silence and darkness at night. Once I'm asleep, though, you could probably shit mice in my ear before I'd wake up.
Anyway, I talked to my brother, and he says there's basically no way that Option 2 would be seen as anything other than a whack shack. Even though I'd swear up and down that I wasn't spanking it in there (and I wouldn't be), it'd still be the kind of thing where people ask questions about it. I don't think the light from the monitor will be awful anyway, if it's facing the wall instead of the room.
What does it say about me that I'm more concerned about my roommates being pissed at me than I am about being pissed at my roommates? I mean, as long as they don't touch my shit without permission or try to sneak pot into the room or something, I'll probably get along with them fine.