Request the project's address and the classification evidence relied on for it, the offering and escrow documents, and confirmation of whether the filing is a standalone I-526 or an I-526E. Separately, assemble your own lawful source and path of funds records, which are about you, not the site. Ask also for the escrow agreement itself rather than a summary of it, and for the subscription agreement you would be signing, since the conditions on which your money moves and the rights you give up are stated there and nowhere else.
Two document files, one petition
Site documents answer whether the reduced amount is available. Your financial documents answer whether your capital is lawfully sourced and traceable from origin to the project account. Prescribed historical tax records may be required, so do not assume that older years are irrelevant.
A gift can be used, but the donor's funds must also be shown as lawfully obtained, and the transfer path documented step by step. The source-of-funds file usually fails on continuity rather than on legality. A lawfully earned sum leaves one account, passes through a relative's account, a currency dealer and a corporate account, and arrives with two of those steps undocumented.
Every hop needs a record that explains itself on its face: the statement showing the debit, the statement showing the credit, and the instrument saying why the transfer happened. Collect them while the money moves, not afterwards.