Good job..ill prefer
1- username
2- a) firstname .......b) lastname
3- email
4- password.

Don't need to confirm password cause user can always recover it from email. Real names are necessary cause they are needed for member search. About rest of the details..I think they should popup next time when user login, so they can fill them out. First time experience should be hassle free.
Login plugins for FB,Twitter,G+,Linkedin should be same way we have right now at the bottom of this forum see more post but with small logos.