Congratulation.
If I were you, I will file 485 right now as well as EAD. Once you and your wife get the EAD, you can choose to use it or not. I think OPT is safer, if your wife want to start work before she get the OPT, she can apply CPT (not work for everyone, check to your wife school's international office first). In any case, apply 485, EAD and AR.
Good luck