If the cosigner is not contributing funds but is just helping secure the loan, whats a fair way to compensate them?

Then I refinance it with a long-term DSCR loan.

Great question: The seasoning period begins the day it's purchased.We do just shy of 100 DSCR loans per month.

I would look at the DSCR loan as the first option.By the way, I suspect you are going to be disappointed by any refi appraisals   ADUs typically appraise poorly   JADUs can lower the property value Vs having the space as part of the primary unit.  

25 inspection, 25 closing, 1 loan.

As far as financing what would be a good loan?  

The most successful loans are those that do not procrastinate and get the appraisers In ASAP so you can get over any unexpected bump in the underwriting process.

Loan Amount: We specify this as a percent of the purchase price.

The institutional firms that do this type of lending (we deal with them every day) have to "securitize" the loans...meaning have their hedge fund/Wall Street backer bless the deal.

@David Matarazzo  Did either of you move forward with them for property loans?