The investment should be irrevocably committed before the application, so the usual sequence is to structure the deal, close or irrevocably commit, then apply.
Structure first, commit second, apply third
Hypothetical example: The order can be uncomfortable because it asks the buyer to make binding transaction commitments before immigration certainty. A purchase conditioned on E-2 visa issuance may still qualify as irrevocably committed when the agreement is binding and the funds are held in escrow for release or transfer once that condition is met; an arrangement the buyer can otherwise unwind at will does not. Reduce risk elsewhere: complete due diligence thoroughly and condition closing on appropriate financial and title matters.
Before any of that, have the draft agreement reviewed for the at-risk question, the control provisions and the assignability of the customer contracts, since all three are immigration evidence as well as commercial terms. Build in time for the business plan, which is a substantial document covering staffing, projections and market, and for the consular appointment schedule. A harvest-season closing date chosen for commercial convenience should be tested against that timetable before it is agreed with the seller.