Once the structure is decided, the letter and agreement are final, and the admission step has actually succeeded. A port-of-entry application is decided the same day; a USCIS petition has its own processing time. Neither should be treated as a date on the client's project plan.
Building the sequence backward
Start from the client's month-end that she must be present for and count back. Allow time for the two drafters to align the letter and the agreement, for the provincial order to issue a good-standing confirmation, and for the household to settle the partner's plan. If the port-of-entry route is chosen, she should travel with a return plan, because a refusal that day is possible and the client's project should not depend on a single attempt.
If the petition route is chosen, premium processing shortens the wait but does not change the test, and the client should not announce her appointment until the approval notice exists. Once admitted, the status is for the engagement described; if the manufacturer later asks her to stay on as permanent controller or to take over a second subsidiary, those are changed facts and the file should be reviewed again before she continues. Keep her Québec firm's other engagements on a separate timeline so that her absence does not create a client problem at home.