Got RFE on H1 extension before H1 transfer - URGENT

[sherry001]

Here's the background:

I'm currently working for company A. I got an offer from company B on 9/13. Then I gave A 2-week notice on the same day. So my last day with company A would be 9/29. The problem is my I-94 expired on 8/30, and I got a RFE on 9/18 on my H1 extension application filed by A. Company B hasn't started the transfer request yet. Company B said they can't start transfer before A respond RFE, while company A said since the last day would be 9/29, they wouldn't respond to the RFE and they would withdraw the application on 9/29.

My questions are:

1. If company B files transfer before A withdraws the extension, would it for sure result in RFE or denial? 

2. If answer is yes, worst case is I have to switch to H4. Do I have to leave the US?

3. Any other options I can try?

Any reply would be appreciated! Thank you all in advance!