Great outcome and percentage on a dollar.

I don't have the 65% to purchase the property nor do I have someone to partner with.My question is: Is there a way to structure this where I can benefit from the seller being willing to carry a percentage, and then I get a loan to cover the rest?

I am not stating that no ADU will add more value per appraisal than the hands off cost, but I expect it to be a very small percentage of them. 

No, not make it better for your next refinance, the rent will determine your DSCR this is a method lenders use as a percentage toward your loan monthly payment the higher the percentage the better it is for the lender and the better the chance of approving the loan. 

Referral fee should be a percentage of the entire Buyer commission, not just what the agent nets after splitting with their Broker.

Somewhere between 1 - 100%  It all depends on the percentages you use for the different markets analyzed, which in turn generates a general percentage of different size properties in these different markets, which then setup a different percentage for each different size range of properties within those markets. 

What is a fair percentage to give to a partner taking on the mortgage but not putting in money for a down payment?

Have you checked liquidity requirements, Debt Service Coverage requirement percentages, Recourse etc...

Though a high percentage of such suites are likely illegal from a technical perspective, that is not balancing out the risk in his eyes.Impossible to answer particular with Covid delays, but does anyone have experience obtaining an adjustment in Hamilton from SF to legal 2nd suite or any feedback?

What are your thoughts about using the profit and putting only a small percentage down on the new primary and investing with the rest?