I-140 Holder Switching job with only 1 year left on H1B Extension

[prashantnayak4u]

I am in Us from about 8 years. My GC process was initialted just before the 5th years of my H1B. My I-140 was aproved without any issues and I got an H1B extension for 3 years.

So my H1B extension is based on I-140 approval and I have already consumed 2 years. With only 11-12 months left on my H1B, is it safe to move to from my current company (say company A) to a different company (say Company B).

Question 1#
If I join company B now, will I get an extension of 1 or 3 years or will I get an H1B Extention only untill the current H1B is approved for?

Question 2#
If Company B starts processing my GC after 3-6 months and if the status of PERM with the new company (Company B) is still pending, will I get an H1B extension with the new company?

Question 3#
Is there any risk considering only 1 year of my H1B remaining? If yes, what risks do I have.

Thanks
Prashant