Failing that the property can be deeded back to the original party, and the lending institution may be satisfied with that.  

And it looks like the institutional quality and low debt features of most DSTs aren’t immune to good ole market forces.

Syndication A is 900 employee with 30 years track record, Syndication B is 1 year syndication graduated from Cardone school of institution run by three people, the Syndication A offering lets say conservative 10% IRR Class B Core ; syndication B like you offering value add somewhere in Dallasville Class C value-add promising 15%IRR.

Depending on where you are, there's probably a large institutional wholesaler that is always hiring.

The FNMA "New Book of Business" instituted circa 2010 (see this SEC document that mentions the term) https://www.sec.gov/Archives/edgar/data/310522/0000950123110... completely revamped GSE underwriting as @Jack B pointed out. 

This isn't the days of having to go through every file by hand.Financial institutions, I believe, are starting to get "stressed" and they will be more proactive in addressing this issue.

Benefits homeowners NOT institutional investors.

First, there is no institutional lender that I know of that would touch doing a HELOC behind a mortgage that did not belong to the borrower.

The individual owner of a seller financed mortgage enjoys a notable advantage over a traditional financial institutions, direct one on one negotiation capability with the borrower. its an advantage for negotiating new terms, adjusting interest rates, and addressing unforeseen issues.We have heard that this is a way for the owner to avoid "Capital gains"?

I don't know of any institutional lenders that do them as one loan right now.