I am on F1 OPT STEM and my wife is on F2. This is the question about H4 EAD

I am on F1 OPT STEM and my wife is on F2. I got my company to start my PERM and I140 on F1 visa. I have the following questions .

a) Will there be any potential problems exiting the country if one starts perm processing on F1 visa ?

b) After my I140 is approved, can my wife on F2 status apply for EAD or should she wait till i get my H1 so that she can apply for H4 and EAD at the same time ?

I appreciate the help.

Thanks.

I think the EAD is only for H4 visa, not applicable for all with I-140 approved.