I asked the wholesaler for proof of contract, but he said is wasn't necessary to show me the original contract.

I am trying to get a HELOC for a property I am rehabbing but the bank wants proof of insurance.

I hope to use this as a proof of concept of the BRRRR method for myself.One drawback: If you have a really good deal, then you may be able to pull out more cash than you have in the deal with the BRRRR method, while with the 203k loan you will have to put up the 3.5%.

Am I to keep all of the checks as proof of rental income for a duration of time?

Therefore I look at what the property will throw off in cash, how easy it will be to rent, what the area is like, how recession proof it is etc. 

We have just sent in counter upping price a bit, also including accurate comps along with another bid from contractor and my proof of cash funds.

This is your proof it was mailed out, on time. 

The way I have always understood it is that the person being denied has to request an adverse letter and a copy of the proof you used. 

Commercial leases are more bullet proof than residential.

Their detailed monthly reports should suffice.On the other hand, as the property owner, you have every right to demand that they provide you proof of the expenses they incur on your behalf, such as invoices.