If they're living and working in the US, those "foreign workers" would be subject to US tax and employment laws, not Canadian.
I understand. Thanks. But that is assuming these are all independent contractors doing no work in Canada.
I agreed with your earlier post that whether the workers are employees or independent contractors needs to be determined.
I think that advising a Canadian poster (or one from the U.K. or Australia or Vietnam or wherever) is outside the scope of this forum. This is despite my knowing of your particular knowledge of Canadian employment law.
But I accept that I may be alone in thinking this.