I have an EB3 green card application with my current employer. The priority date is 2011-June.I have my I140 approved (in 2012). I just got my H1b visa extented till 2017 October during my 7th year extention

Now my current client is offering me a full time position. Their lawyer has evaluated my experience and qualification and told me that they can apply for green card in EB2 category.And port my EB3 priority date when time comes.

I am planning to take the new position with the client with the hope that they can port my current priority date with the EB3 application.

In this scenario.

1.When the h1b gets transferred from my old employer to new employer, based on the old I140, am I still eligible to get 3 years extension?

2. Incase I do not get a 3 year extension after h1b trasfer, what will be my status if the new GC labour stage is not cleared before the new h1b expiration date?

3.Is there a situation when I could loose my old priority date in this scenario?.

4. Do you see any other risks?