H1 approved for Consular Process and another h1 transfer in process- Most Urgent

[dkrajput]

Hi,

I work in company A and i applied h1 transfer for company B in PP. It went in RFE and it got cleared on 17 th dec and it said it is approved . But when we got document on 28th dec it came with denial of Extension of Stay(due to unpaid  for some months on medical leave) and approved petition .In denial in the last it written that now beneficiary is without lawful immigration status , so presence in USA is a violation of law.On 21st dec i started another h1 transfer for company C in PP( I thought B petition is approved without any hitch) and it is still in the process.I am still working with company A technically ,but not after 28th dec when we got Denial notice.
I have a valid visa with company A till sep 2017. 

My amendment with company A was also in process with regular processing.

Questions:

1. Can i go to mexico in and out on company B petition? is there any problem if another h1 (company C) is in the process? Will there be any problem at the check point due to EoS denied? ( I heard that if h1 is in the process you shouldn't go out of the country, So one petition asking me to go out and another asking me to not go , what to do ?)
2. Shall i wait for company C decision and then take decision? talked to company lawyer of C he told that he can challenge the decision ,suppose if decision comes same and he is ready to challenge ,can i stay in USA till that time?
3. If i want to join company C, do i have to ask company B to cancel petition or no need?
4. Can i go India and wait till the decision of C comes and then join ? is there any risk? Will i have to go stamping in India again?
5.Shall i inform company A that my h1 petition invalidated ? Or when will they know? Can they do something to put me in danger to save them self because i was not paid on medical leave? 

I appreciate for you time and response.
Thanks,
D