It shouldn't be an issue for you to represent her, you'll just have to show it's with her permission. Either she'll need to attend to verify that or you'll want some kind of signed note from your wife authorizing you to act on her behalf.
Stanton, could you please explain what representatives can do and what they cannot do?
Can they request disclosure or stay on their behalf or it must be signed by their defendants?
Can they go to the trial instead of their defendants or just with their defendants?
Can they plead guilty or request adjournments, stays, etc. during the trial if their defendants are not present?