It offers alternative insurance for your situation.

Other alternatives tend to cause drama.

(Alternatively) Can I buy chunks of other people's "wasted giant back yards" around the property, clump them together and gain access to a road, and redevelop it into a micro-community?

@Bobby Valcin the FSBOs aren't on the MLS so you must be using alternative sources.

Has anyone tried the following sites and have any recommendations on the following sites?Rex, Redfin, Roofstock or Redfin

So, you either accept a lower return, find alternatives, or wait for oppurtunities down the line.

Alternatively you can also read the books in the following Biggerpockets page - https://www.biggerpockets.com/blog/wp-content/uploads/2018/11/Best-Real-Estate-Books-Ever.pdfI would say spend enough time in grinding the axe before you start chopping the tree.  

If you choose that route, you could use some of that $20k towards improvements on a fixer.The alternative would be to find other low priced metros to play the cash flow game.  

Any ways around this hiccup or alternate methods of procuring a loan would be greatly appreciated.

Alternatively, if the property doesn't have an ADU, but the owner would like to add one, it may not require a zoning change, if the property is owner-occupied and they ADU can meet the setback requirements.