I... don't really know what to choose for the first one. I suppose I'd choose to be "constantly monitored". I think I'd go absolutely crazy if I were 100% alone for my whole life. I get lonely when I've been alone in the house for two days, nevermind forever. So even if that only meant I'd only be alone while I wasn't out and about, I think it would bother me too much. Although I'd probably choose to be alone if the person who I had to live with literally was only there to monitor me and report back to someone. I don't like the idea of constant surveillance but if it were someone who for some reason just had to stick with me for the same reason I had to stick with them, I'd probably manage. It seems like something you'd just get used to.
Definitely darkness. Bright light gives me a headache after too long.