Before adding her on your

I-485, first ask her to renew TN, which get one more year in hand. Then after 60 days, add her on your I-485 or you two file at the same time.

Once add her to the I-485, she won't be able to renew TN any more. You should file EAD+AP with I-485 at the same time for her. Hopefully you will get EAD+AP after 3 months, then she can use EAD to work and no need to renew TN.