I have never tried to sleep with an eye mask, but I sometimes put a small washcloth folded up over my eyes. My mother once implied that was dangerous, like that it could suffocate me? I don't see how, but maybe it's not the best idea.
Re light at night, I very much dislike having any light leaking into the bedroom. We have a nightlight in the hall that I actually swapped out to get one that wasn't as bright. But if we close the bedroom door, it gets too hot. Or if there's no light in the hall, it's dangerous because of where the stairs are. Maybe it will be better after we move....