Changing Companies on EAD & GC

[kiku]

Hello -

This might be a repeated question, but wanted to get opinions.

I currently have EAD for myself and my spouse. I am still on H1B status while my wife is using EAD for work purposes.

1) Can I change jobs without using EAD, but still have it?
2) In the above case, I presume that my wife will have no status because I want to move on H1B.
3) If I move on to a new job in similar current job role on EAD, and later get GC, should I be in the same company for 6 months+?
4) After getting GC, for how long should I be in the same position? Or there is no such clause?

Please let me know.

Thanks.