Work backwards from the state licence rather than from the border. Admission in this category is granted for a period not exceeding three years and is tied to the employment described, so the application itself can be made quickly once the offer is firm, but a licence application filed late will leave him lawfully present and professionally idle.
The slow document sets the schedule
Two clocks run at different speeds here. The immigration clock is short: with a firm offer, a complete letter and his credentials in hand, a Canadian citizen can present the request at a port of entry, and an employer petition takes as long as processing times say it does. The licensing clock is long and unpredictable, involving a board’s meeting schedule, possibly an examination sitting and often a third-party evaluation of his education.
If crews are expected to be staking by April, the licence file should have been opened the previous autumn. Two improvisations are worth naming so they can be avoided. Beginning the American work remotely from Saint-Lucien before admission raises questions about who employs him and when the employment began.
Travelling first as a visitor and then performing productive work is a separate problem with worse consequences. Neither is a scheduling shortcut.