My 6 years of H1 + L1 is coming to an end in June 2017.
Currently I am working with Company A (For 9 months now).
Another company "Company B" had filed my GC in EB2 and my I140 was approved last month. (Both the companies are run by the same set of people)

Now "Company A" is filing my H1B Extension with the approved I140 from "Company B". I checked with my employer and they say it is okay.

But I have the below questions in my mind.

A response will be highly appreciated.

1. Is it okay to file H1B extension this way or is there any chance I might get RFE? (Because "Company A" is not holding the approved I140)
2. Will the 6 months rule for I140 apply here to retain the Priority Date?
3. Will there be any problem for my future extension (GC process) if I change to "company C" after 6 months from now?