Like I said, Weasyl there is actual name changes. You just gotta talk to an admin about it. FA, though, they're never going to get name changes. That'd be the only place you'd have to move if you ever wanted a different username. If you cna't change your FA, then yeah, do use the handle you are most known as as your signature.

On "Furry Related" FA does allow furry artwork, and there is Human-related communities over there. I'm a pretty human/oid artist myself. I think my more favored art on FA is the human characters I draw anyways. When it comes to online communities, what you get out of it is what you put into it, so if you'd like more human-central audience, keep posting up the content you like to draw. (http://www.furaffinity.net/user/humanartistsoffa also, check out this place to share human art/commissions/find artists). There's also a pretty large SFW community as well. I can vouch, 90% of my content is sfw, the other is usually gore, while FA is made of about 75% sfw posts believe it or not.

Its just harder to get seen because the keywords searches aren't as easy to find. People know what they are looking for when they want to see vore, or pokemon. They just type it in. But for sfw art non-fanart related you gotta work with vague tags like human dog male female pink purple and hope people look for "male human" or similar searches. It's harder for people to find art that doesn't have a very specific theme like fanart and fetishes.