EAD and H-1

Right now I am holding F-1 and will graduate in this Fall, I apply I-485 and EAD with my hu*****and in this July, I-140 and I-485 is pending now. My question is:
1. If I use EAD work in January 2008 and apply H-1 in April 2008, is there any effect for my I-485?

2. What if I use “回美证“ go back to china in December?


Thanks a lot!!

_:o _:o