I had no problem obtaining a TD visa for my Daughter to move down to Tennessee with me, on the TD students cannot work and unless your wife qualified for a work visa, she would be unable to work. As I moved down ahead of her, for the TD I had my lawyer prepare a petition letter with both a copy of my TN visa and passport ID page attached. No problems with having the TD issued. If you are travelling as a family, you can appear at the border in person with them (and your valid TN) and save the cost of having a lawyer prepare the letter. For the school (high school) we had her Ontario transcript and immunization records. We had both a registration form and medical exam form which had to be completed and turned in, these were supplied by the school board office and we could use the doctor of or choice. All in all it was very streamlined.