I use Stessa only for the tracking feature (transactions).

Start learning with books, podcasts, courses, networking, building a support system, and preparing for financing.

Was the July 2015 transaction a purchase or refi? 

I’ve educated myself with books like Rich Dad Poor Dad and real estate podcasts, and I know I’ll succeed.I’d love advice from others who’ve been in my shoes: Is it okay to start investing in a different area if one strategy isn’t working?

Right now, the technology is not yet suitable for small projects, simply because the transactional costs are way too high and there's no secondary market.

In addition, the capital outlay starts long before any income and the detracting of something from the primary structure even if it is just yard space.As indicated, my original protege made a lot of money (over $500k) on a land transaction associated with a large count ADU development.  

In particular:(1) Should I hire a law firm or collection agency to facilitate the transaction?

Get a development standards book so you can understand what and why a engineer should do something.

A few recommendations - learn as much as you can from books, podcasts, and attending free or low-cost real estate investor meetups in your area (in-person is best).

This is the oldest professional tenant trick in the book, but you should definitely get a lawyer on board now.