I worked for Employer A for 4 years during which he filed both PERM and I-140 and got approved on September 5th 2008. Last year I went to India in December 2010for H1 stamping, my Visa was rejected and LCA was sent back to USCIS. I applied for another H1 through employer B and went back to USA this April. My priority date is January 7th, 2008 and it is going to current in December to apply for 485.

1) Can I apply for 485 through my Employer A (previous employer) lawyer? He is willing to give me employment offer.
2) My Employer A is saying that, if I am not under his payroll when we are applying for 484, there is a chance that we will RFE and the lawyer will hard time support those queries. Is that true that I need to go back to my employer and under his payroll while applying for 485?