Certified translations, bank record retrieval charges, accountant letters, notarization, courier costs, and the currency spread on international transfers. None of it is investment capital, and none of it is a government charge; official fees are separate again and should be confirmed at the time of each step. Budget for the donor's side of this work as well.
Delay the non-refundable commitments
Sequence spending so that the documentation question is answered before deposits become non-refundable. If the source cannot be evidenced, better to learn it while a deposit is still recoverable than after a lease has been signed. Ask advisers for an itemized scope covering the funds analysis specifically, since it can be the largest part of the work.
Do not inflate the transferred amount to reach a figure someone has advertised as a threshold. Add one further sequencing rule to that spending plan: buy the funds analysis before the business decision, not alongside it. Where the source of capital is a gift, the question of whether that source can be evidenced is the one most capable of ending the plan, and it can usually be answered on a preliminary basis from a short review of what records exist and what the donor is willing to provide.
Everything else — the lease, the valuation, the plan — is worth more once that answer is in hand. Hypothetical example: a prospective buyer of a landscaping contracting business spends a fortnight and a modest fee establishing that the donor's records are retrievable, then negotiates with a confidence that changes both the pace and the terms of the transaction.