L1B to H1B Transfer currently on i94


I am working on L1B in US for company A and planning to get H1B this year with company B, my L1B expired but have valid i94 till 2015. I got a consultant who agreed to do my H1

Please answer my below questions:

  1. can i continue on L1 B even after getting my H1B approved? i cant go back and enter US again as my L1 visa is expired already?

  2. Can i still work for Company A if they are ok to accept H1 or cannot do as company B can create legal issues?

  3. if i do premium processing, still i have to wait till oct1st to work for new employer right? in the mean time if Company A sends me out of country, Can i re-inter once it is approved or by when i can expect response if applied on premium by April1?