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.  

Often, lenders will not act until the differential between current interest rates and the interest rate on the subject loan reaches a certain point.  

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.

A few thoughts- do you have any equity in the car with the $20K loan? 

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?

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

5% down federal loan How did you add value to the deal?

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