I am presently on H-1 working as a Physical therapist for a company ,A. Its being sold. The company B who takes over, wont know if the deal goes through goes throug till 15 April. They have indicated they will hire me but they might not be able to file the transfer til 15 may. My Questions are

1) Should I file H-4B to avoid going out of status for those 10-15 days ?
2) If I do, what happens if my H-1b petition is approved before H-4B does?
3) How do I get my status changed back to H-1B, if my H-4B is approved after H-1B? (Can I use automatic revalidation by going to Canada or is it possible to do it without stopping work at all by filing COS)
4) What are the risks, if my husband looses his JOB, when my H4B is pending

My I140 is approved with company A & I94 is valid till mar 2012