Options after 485 denial---need help from Xiaobaitu and other ex

Please help!

My 140 (NIW) was approved and 485 is pending. Now I want to quit my H1b visa and use EAD instead. My questions are:

1) if 485 is denied, do i need to leave the country immediately? what options do I have?

2) I heard one cannot appeal for a 485 denial. Is this true? Can I file a motion to reopen?

3) If I can file an appeal or a motion to reopen, can I file a new 485 during this period?

4) Is my EAD still vaild during the time of appeal or motion to reopen?

Thanks so much!