Fix the immigration requirements into the transaction documents first, then set the closing date. Reversing that order forces the applicant to argue from terms that were not drafted for the purpose.
Draft first, close second, open third
Hypothetical example: A seasonal enterprise creates a hard commercial deadline, and hard deadlines encourage shortcuts. The workable sequence is to identify the requirements while the agreement is in draft — commitment and risk, nationality of the ownership chain, the investor's operating role — then negotiate terms that reflect them, then close, then open. Where the season simply cannot wait, the honest position is that the transaction may proceed for business reasons while the immigration outcome remains open, and the household should decide knowingly whether it accepts that exposure.
What should be avoided is the assumption that an approved purchase implies an approved status. Ownership of a U.S. business does not authorise the owner to work in it, and arriving to run the operation without the status that permits it is a separate problem with its own consequences.