Quickbooks does not have a good platform for note servicing and accounting, but can be functional if you are accounting for only one or two notes.  

It is stated therein that the use of a functional or equivalency test to classify property (1) as inherently permanent when it is not itself physically attached to the land, or (2) as a structural component when it is not an integral part of (and therefore a permanent part of) a building, is no longer the criteria to be used to classify property.

For instance, I have a spot that had a very weird floorplan when I first bought it (which drove buyers away), but I could see that with some relatively minor work, the floorplan could easily be changed to be much more appealing, and much more functional...the property was turned from a 2 br 1 ba into a 3 br 3 ba, which transformed it from a cashflow negative property to a significant cashflower.With prices so high and deals so hard to find, value add strategies are often the way to go!

You will have remaining entitlement left over to purchase again in Oregon, but it will be limited as a function of the current entitlement.

Who will do quality control and make sure everything is functioning properly, furniture is not broken, grounds are maintained, etc?

It passed the septic inspection and another inspection showing that it is functioning great.

It was very distressed, the roof leaked, 1 of the 2 bathrooms was in non functioning, and it came with 2 "tenants" living in trailers that we had to remove.

My goal is to convert the unfinished basement into a fully functioning ADU.

Should I take this out to buy an investment property, functioning like an "all cash" purchase or should I use it as a down payment for a more expensive property and take out a mortgage? 

The time to positive cash flow is mostly a function of how close property is to cash flowing at acquisition and the rent appreciation.