Dependant status follows the principal. TD status depends on the principal maintaining valid TN classification, so if the engagement is restructured in a way that requires a fresh determination, the dependants' position has to be reviewed on the same timeline rather than assumed to carry over.
Review the dependants whenever the principal's arrangement moves
TD dependants — a spouse and unmarried children under twenty-one — are not independently employment-authorized, and that does not change because the principal's contract has been rewritten. What can change is the period covered and the documents each family member should carry. If the American company converts a contractor engagement into employment and a new determination is made, plan the family's travel around the principal's, so that nobody is admitted for a period that no longer matches. Children in this situation may attend school, which is a separate question from work authorization and is often confused with it. Where a spouse also wants to work, the honest starting point is that TD does not permit it, and that the spouse's own qualifications would have to support an independent route assessed on its own facts.
Hypothetical example: Noura, a wildlife biologist, has a spouse planning paid remote consulting while the family changes travel dates. The family should treat the physical location of the spouse’s work as a status issue: TD permits study but does not authorize paid employment, including remote services performed while in the United States. If the spouse intends to keep working, an independent work-authorized route must be assessed before the move. Noura’s own file still needs Canadian or Mexican citizenship, prearranged employment in a listed profession and that profession’s required credential. Passports, marriage and birth records, and each child’s age should then be aligned with the principal’s requested TN period.