I don't think the fight should include Bella and Renesmee. As Elizabeth said, they wouldn't fight for Renesmee's sake, so by the time Bella is a vampire, there would be no fight. But before that, I'd say the wolves have a pretty good chance. Firstly, because shape-shifters regenerate, they heal in seconds. Secondly, because wolves get bigger the more angrier they get. Thirdly, because vampires find touching werewolves unbearable because of how hot they are. Finally, because werewolves are stronger, tougher, bigger, better, and faster than most vampires. Plus, they have acute senses, in Breaking Dawn, Jacob could hear someone playing all the way from the beach!
A shape-shifters bite can tear the skin of a vampire easy, like with Laurent. Bit his head off. The problem is there a bit too cumbersome, maybe some would be better off fighting in their human forms.