The case:
A person worked for firm A on H1B and had a RIR LC pending in BEC, later changed to work for firm B on H1B transfer and have an approved I140 via PERM but cannot file I485 due to retrogression.
Assume:
Firm A has not revoked his/her H1B and RIR.
Questions:
1. Could he return to work for Firm A without another H1B transfer?
2. Could he continue the green card application via RIR LC with firm A as it has a much earlier PD?
3. Are there any the other negative implications to the GC?