H1B 7th year extension and transfer at the same time

[Bahubali]

Hello, 

I am in 6th year of H1B (expiring September 30 2017) through company A and my I-140 approved over two years ago through employer A, I got an offer from Company B and need to file H1B transfer to company B. I am in the process of applying for extension through company A as well. 

1. Will there be any problem to my transfer petition to company B? Since I never filed any green card petition with company B.

2. Will there be any problem with filing extension through company A and applying for extension with company B at the same time? 

3. If my petition with company A is approved while petition with company B is pending and I want to work for company B. will there be any problem?

4. If my petition with company A is denied, will there be any impact to petition B? 

Thank you.