H1B Transfer A To B - Out of Status and A to B to C

[cricket2016]

Hi,

I was working for a company A on H1b visa and my employment came to end in December 2015. My I-94 with the company A expires in March 2016.

Company B filed a transfer in regular processing after 3 weeks of my end date with company A i.e. in 3rd week of January. I have a I-140 approved from the company B as well.

I haven't started working for company B and company wants me to start upon approval. I have received the receipt for company B.

Questions:

1. Whether i am out of status and is it OK to stay in the USA till i get an approval?
2. Are there any other issues in this?

Meanwhile, if suppose I get an offer from company C in couple of months , can i file a H1B transfer with the company C using receipt from company B or company A.? I wouldn't have pay slips from January on wards neither from company A or B since i am not working with either of them.

Any help or suggestions for this scenario is appreciated.

Thanks