U.S. credit is not necessary as the loan will be assigned a 680 credit score. 

Not sure about your jurisdiction, but in Chicago most leases have assignment clauses.

@Noah BaconSpeakers already assigned or still open for applications ?

The buyer and seller don't meet until closing of it's an assignment deal (which I don't do much anymore).

If I’m the wholesaler, how do I show proof of funds when I’m not the one buying the house, and what do I do when the potential buyer im assigning the contract to wants to go see the house.

Perform the same task in each app to ensure a fair comparison.Load a property with pictures and details.Market that property.See what your marketing looks like from the public's perspective.Submit a fake application to see how easy the process is.Run a credit/screening report on yourself.Enter a maintenance request, assign a vendor, and attach a fake invoice.Enter charges to the tenant's ledger.Enter recurring charges and automatic late fees.Sign documents electronically.Run owner reports.After testing a few apps, one should clearly stand out.

Every american is assigned a SSN at birth.

Now if you read your mortgage small print you might have Assignment of rents clause  ( when i was lending I put that into all my security docs). 

And bait and switch, 10 day Option periods for 10 days for $100 to surf for other Buyers to assign to - don't get me started LOL!

Enter a maintenance request, assign a vendor, and attach a fake invoice.