I don't know about your subforum question. As for the password question, I don't know of any existing mod that does that (but it doesn't mean there isn't one out there somewhere). There's this one:
https://vborg.vbsupport.ru/showthread.php?t=264515 but it's for vb4 and only enforces length. I haven't looked in to it, but it could be that the same method could work on vb3, and I'm sure you could add checks to enforce conditions other than length.