I have same experiences

My hu*****and applied I140 and I485, before I came to America with H4, but he never used his EAD until we got GC. I had to wait until his priority date is available. We tried to file my I485 petition before his priority date available but the I485 was returned. So I think if you filed your I140 is earlier than 01/01/2006, your hu*****and can file his I485 in November, or he can not file it. I do not know the answer to your second question, I believe he will lose his legal status after you use your EAD (not H1 anymore).