Can I work on corp to corp when H1b transfer is under process for same company B?

[blackpearl77]

Hi,

I am currently working for Company A on corp to corp.
I have got a job offer from Company B and my h1b transfer is under process. I got a RFE and Company B employer is working towards it.

Company B is asking me to join them on corp to corp basis until my H1B transfer is completed/approved.

Questions:

1) Can I join Company B(who has initiated my H1b transfer) on corp to corp for the same client/project?

2) Is this legal? If yes,

When my current employer(company A) applies for H1B amendment for change of location, will my H1b transfer be overridden?
What if the approval of Change of location comes first and then the H1B approval?

3) Does this route of going on corp to corp when my H1b transfer is under process for same project/client affect my h1b transfer/petition?

Please clarify.