[list][*] Games, yes; manga etc... well, so far as I know them (haven't read Forbidden Scrollery); Akyuu: please bring a salt mine.
[*] Yes.
[*] They'd need a very good reason to be here. And no replicating SSiB's ridiculousness. Also a reason to be here that doesn't get everyone trying to get them to [i]go away[/i].
[*] Obviously not common. Obviously possible because Youki was a thing, but definitely not common.
[*] Given that the Alice bio involves Makai and being a maid, take a guess.[/list]