Fair means pale, not hot, but back then, having a tan was considered ugly
Fair is an old world term that was used in reference to beauty. People back then would also wear makeup to make themselves appear more pale (fair). This is where "crack a smile" originated from, because smiling would cause the makeup to crack from what I've heard.
Anyway, let's get back to the topic. It so far doesn't sound like werewolves are going to have any real involvement in Dawnguard, but there is a possibility that they
may be getting a little bit more than just a perk tree. I'm still assuming that they are just getting the perk tree and nothing else, which would be fine also, since they are severely underpowered in vanilla. I just don't want to do any crazy speculating until there's a little more info about Dawnguard.