H1B EB2 clinical research, GC initiation and residency plans on different H1B-feasible?

[mumdoctor]

Is it possible to file for a different H1B visa with different employer (say company B) (with different job responsibilities clinical research versus medical residency) if company A has already filed for my Green card and the application is somewhere between approved I-140 or waiting for I-485 (waiting for the PD to be current). I don't think AC-21 can be useful in my case as my current job responsibilites will definitely be more than 50% different than being a resident..

I am working full time right now and company A is willing to file for my green card under EB2 category. Depending on my job funding, I will be going part time in June 2012.

My questions are

1) When I go for my next stamping at Mumbai consulate after June 2012, will my part time H1B raise a red flag? (I had received a 221g query last time in April 2011)

2) Will me being part time with company A affect my GC application in process? If so, how? (GC application is for future job)

3) Assuming that I go part time (before/after filing for PERM-Would that make a difference on PERM application too?), and reduce my hours to 8-10 and then file for a separate full time H1B for my residency through different employer---Would I have any problems for getting the second H1B visa (as(1)My GC is pending with company A and 2)Job responsibilities are more than 50% different)

4) How competitive are Murthy's rates for simultaneous filing for GC as well as H1B extension? would they give me discount for hiring for 2 services simultaneously?

Thanks for your patience and look forward to hear from the experts