I suspect a decent VA could access public records and build a mainling list for you  or check Property Radar and see if there software will do that for you..

Go to BUILD YOUR TEAM at the top of the screen and look for local investors or meetups in your area.

What rate, term and amount borrowed did you get for the ADU build and what was the cost?

The seller has the two lots legally separated, but due to deed restriction imposed by the subdivision development, found that building a house on the “tennis court” lot was not allowable. 

They said we have to build new walls because the old walls are directly on the concrete, and this is not allowed.

In my market, which is a fairly economical place to build, I am friends with full time builders that are in their properties about $150k/door for construction level finishes.  

The options are, demo the lot, split the lot and then sell 2 lots to the builder or build myself.

I do STRs, building some now. 

Keep in mind that only the "building basis" can be segregated and will benefit from accelerated depreciation.

A reserve is unnecessary, but I still keep around $15,000 - $20,000 in my account.The point is, that you should sit down and assess your finances to determine what the worst-case scenario may look like, how much you would need to cover it without impacting your life, and whether you will need to build a reserve.