Well, in terms of appearances of characters, it depends. In the case of the Belmonts, it depends on how you see them. For example, at first they seemed to be rugged warriors who fought evil, but that changed. They now seem to be somewhat refined. In other words, to me at least, it's like a poor person living "off the grid" becoming upper middle class. They're actually fully clothed instead of wearing that armor that seemed to not cover everything. They actually seemed barbarian like and now it's like they're nobles.
I don't know. If you ask me, the Trevor from CoD was the best example of what a Belmont should be. He was buff, but not overly muscular and his clothing reflected the times. As for Alucard's appearance, it is about what it should be. Being the son of a count, his clothing should be that of a nobleman. And his "inhuman" beauty is standard for how vampires are described in most novels these days.
Regarding an incubus, he should be a "pretty boy". After all, if an incubus is the male equivalent of a succubus (as we all know) then he should be attractive to women and from what I know, most women like pretty boys.