Assess the actual qualifying relationship and identity evidence rather than presume a shared surname.
Document the relationship accurately
A surname alone neither proves nor disproves marriage. Keep each person’s identity record coherent, and remember that TD status does not authorize employment.
Build a separate identity and relationship packet for each family member: passports, marriage record, birth records for children, and genuine name-change documents. Matching surnames are unnecessary, but unexplained differences across records can create avoidable questions. The principal separately needs Canadian or Mexican citizenship, prearranged work in a listed USMCA profession and the required professional qualification; permanent residence in Canada is a different fact. TD dependants may study but cannot work, so the spouse should decide whether planned U.S. employment requires an independent status. Do not describe household business ownership as proof that the TN job is permissible, because U.S. self-employment is barred.
Hypothetical example: A Sainte-Catherine-de-Hatley pharmacist will work for an unrelated U.S. pharmacy, while her husband retains his birth surname. Their marriage certificate, individual passports and the children’s birth certificates establish the family links more reliably than a shared name would. The pharmacist checks her profession-specific education and the employer’s supervision letter; her husband prepares a TD application but postpones accepting consulting assignments. If he wants to earn income in the United States, the family must assess his own authorization instead of treating the principal’s approval as household work permission. They should also keep a Canadian PR card distinct from evidence of Canadian citizenship.