Two EAD from different categories

I have some good questions.
Currently I am working using my EB-2 based EAD which will expire this Oct.
My wife probably will get naturalization in May. So after she becomes an us citizen, can I apply for another I-485 family based along with EAD application?
Does the new EAD will replace my current EB-2 based one once it is approved since they are from different catogories?
Can I continure work for the same employer within 2 different EAD during different time periods?

Any reply would be highly appreciated!!