Assess whether the pilot and documented commitments support the case and how much expansion matters to the future-capacity argument. Filing before opening may be considered with credible evidence; it never requires presenting a condition as fulfilled. Waiting may add evidence or costs: compare those effects on the actual facts.
Choose the filing date by evidence, not by opening day
Canadian citizens generally need an E visa rather than seeking admission without one, so build in application preparation and an interview step when setting milestones for the opening. Keep permit dates, contractor schedules, and hiring commitments loose enough to absorb delay. Intent to depart when E-2 status ends remains relevant, and E-2 is a nonimmigrant classification, not a green card, whatever the expansion timeline suggests.
Two calendars are running and they answer to different masters. The construction calendar moves with permits, contractors and seasons, and slips without anyone's permission. The application calendar has its own steps, including preparing the E application and attending an interview, since a Canadian citizen generally needs an E visa rather than seeking admission without one.
Hypothetical example: a filing date is chosen so that approval will land in the same week as an opening, and when the permit is delayed the application is already committed to a description of facts that no longer holds. Choose the filing date by asking what the evidence supports on that date, then let the opening move independently. Keep hiring commitments and contractor schedules loose enough to absorb a delay without breaching anything, and note that intent to depart when E-2 status ends stays relevant however permanent the expansion looks on paper; E-2 is a nonimmigrant classification.