Priority Date retension and interfiling eligibility

[varun1234]

Our situation is below

Me(Priority Date Year 2012, employer A) and my husband(Priority Date Year 2014, employer B) both work on H1b and have approved I-140 on EB2 for more than 180 days. We are waiting for dates to become current. Now i want to move to H4 - EAD on his I-140 due to Job flexibility on H4 EAD

Can you help us with below
1. Will my I-140 be still valid if my current employer A does not withdraw or revoke ?? Can employer A still go head and file I 485 for me when date becomes current even though i am not working for them ??
2. If i decide to change again from H4-EAD to H1B(with same employer A) in a year or when my PD date becomes current , can i change from H4 EAD to H1 and file I 485 ??
3. Since my husband also has approved I-140 from employer B, can he use my Priority Date of 2012 (2 years early than his PD) when it becomes current using inter filing or conversion and apply for 485 using my PD from employer A??

Thanks