There's a bit of a difference - a little more fear, and a lot more murmuring of how dangerous dragons can be. In general, Monsters fighting back gets that treatment: how they're definitely a threat to normal people, while Witches deciding to fight back are given the "all of you Coven people are like that" but aren't thought of too badly in comparison.

EDIT: Also I somehow just missed your second question, whoops. Characters can live alone, but they're definitely encouraged to have roommates - a lot of places that offer solo housing (such as the apartments) do still have a more communal feeling though, so they won't press too hard. Characters going solo in a giant house will get some slightly disappointed looks though, since that's a bit of a waste of space.