(a) Based on RFE statement, I think that you are right. You can submit the approval notice of H1-B from USCIS to show your establishment of the two year foreign residance requirement. I have a similar situation with you. But your RFE text is NOT complete here. Could you please transfer a scanned original text to my QQH? If I can get your scanned file, I can deeply think what is my case.
(b) I submitted my I-485 at a similar time with you, based on an approved EB1-140. For your case, you can show your approval notice of H1-B to USCIS. Currently, I am trying to apply for H1-B via an university. If I can get H1-B visa, I think it is OK for me.
Anyway, the original RFE text is important for me to understand what USCIS is requesting from you.