You can find a broker to work under that charges you a flat fee per listing/ sale, instead of a percentage. to save money. 

The a percentage can be a quick qualifier or dis-qualifier. 

I'm doing some research now but perhaps someone could shed light on the importance of carry-back percentages?

Or you could just write up a contract that they are allowing you to oversee the maintenance and management of the property in exchange for a percentage of the profits. 

All of that sounds pretty standard except for the percentage of the security deposit.

I thought pulling 100k in bank mortgage to use cash for other investments, pay them a percentage for the usage and would still have approximately 700$ monthly payment on 20yrs 5.5%.

It also shows the gradual decrease of the loan balance until it reaches zero.annual percentage rate (APR)This is not the note rate on your loan.

If so, what percentages are typical for these fees?

I think a percentage based on the ARV - (Purchase Price + Rehab Costs + Holding Costs + Any Debt Service).

On the flip side if we keep it until the loan matures (8 years) we’ll have a nice nest egg to fall back on assuming the housing market stays in good shape, and it’ll likely continue to appreciate but our cash flow as a percentage of the equity won’t be great.