Commit the funds before applying, but structure the commitment so a refusal does not destroy the money. Escrow released to the seller on issuance and returned only on refusal satisfies the requirement that capital be irrevocably committed while protecting the buyer, and it is the standard answer to this sequencing problem.
The problem is committing before you know the answer
The category insists the investment be made rather than promised, which puts a buyer in an uncomfortable position: spend first, apply second. Escrow resolves it. Funds placed with a third party under an agreement that releases them to the vendor when the visa issues, and returns them only if it does not, are treated as committed because no other use of the money remains open to the investor.
Around that central step the ordinary sequence runs as follows. Incorporate in the state, open the enterprise's bank account, execute the purchase agreement, place the funds, make the expenditures that can safely be made, then file. A Canadian citizen applies for the visa at a consular post, so allow for appointment availability and for the review time E cases attract.
Where the buyer is already in the United States in another status, a change of status is possible but produces no visa for re-entry after travel.