I think that as far as writing your own characters into the Angels Fall community that it would be cool to start an independent storyline if you would like. The characters can have ties to some of the other characters, like your character could know Father Bill from the Church or could like to go down to Murphy's for a pint or go to the Diner every Saturday morning for breakfast, but you shouldn't feel obligated that you need to join in the main storyline that is going on.
I am concerned that the main storyline is SO dominating the community right now that it is a bit intimidating to new community members who want to jump in and start writing, and that is definitely NOT what the community is about. It just sort of turned out that the story has gone the way it has, and a lot of that had to do with us learning how to write with each other, but I think that the existing community members would all agree that having other storylines within the community is a really good thing. I myself have just thrown in two characters totally unrelated to the major plotline that you are welcome to tie into your characters if that would make you feel more rooted.
Looking forward to what you are going to write,