H1 Transfer with employer B got RFE, Original H1, I94 with A got expired. AM I legal in US?

Hi,

My H1B with employer A got expired on 30/Sep/2017. Employer B filed for my transfer on 29/Sep/2017. It got RFE now due to normal processing. RFE is something which we can’t defend.

Meanwhile I got an offer with C who is ready to file for transfer. Am I legal in US? Can go ahead with employer C premium processing while employer B RFE is in process.

Also, can I change to H4 if I want to?

Please someone respond.

Thanks,

Yagami