TD does not authorize work, including participation in the principal’s project.
Keep the testing role separate
Identify where the spouse would perform the work and what duties are proposed. Payment through another entity is not independent permission to work in the United States. An eligible spouse or unmarried child under 21 may study in maintained TD status, but the principal’s TN authorization does not extend to the household’s paid project work.
If children's school records or a spouse's own documentation were part of what raised questions, address those specifically rather than assuming the family side will resolve itself once the principal issue is fixed. A principal TN applicant must be a Canadian or Mexican citizen with prearranged work in a listed USMCA profession and the profession-specific qualification; Canadian permanent residence is a different status and does not create TN eligibility. Before any productive task begins, the spouse needs a distinct immigration classification that itself carries employment authorization; a recruiter willing to place both spouses cannot substitute for that requirement. A spouse counting on working should raise that with counsel early, because TD permits study but does not permit employment, and remote or unpaid activities require individual review for an outside employer.