There are loan programs that offer buyers up to $50K in cash not a mortgage & no collateral to use for renovations.

This is a start, also if you have any savings you could look into savings secured lines of credit at a lot of banks, but basically they use the savings account as collateral and will give you a line of credit against those funds...  

I am assuming that they are only reviewing the collateral file to ensure a complete chain.

For selling notes, Paperstac is a good platform but when buying the notes it is all about who the seller of the note is (the counterparty) and are they legit and do they have the property collateral, record keeping, etc.  

The audit verifies that all of the collateral is there or not.As for completing your due diligence, yes it should be done in advance of signing the sales agreement. 

They can have the strategy to buy 1-2 properties dedicated as collateral to help pay off their loans one day.

I've heard about blanket loans or  cross collateral but that's outta my realm as of right now but gonna be looking into it more

I already own my own home that I still pay a mortgage on 2 pieces of land I own outright but not sure I want to use the house as collateral.

The other plus is you would essentially be bringing cash to the investment table instead of real estate collateral backed loans which require much more stringent underwriting.

You can use it as collateral if you default on the property, but that's about it.