2) You filed I-1485 and received I-485 based EAD
You're in AOS after F-1 expiration, legally.
With an EAD, you may work before/after F-1 expiration.
I, if in your case, would COS to H-4, even consider using EAD.
http://blog.wenxuecity.com/blogview.php?date=200710&postID=20710#H