I love how Mint was "semi-automatic", and did a decent job on its own although you needed to come in and tweak categories.All this to say, are there any other Mom & Pop investors out there with more complex personal finance that have found useful software solutions? 

The Rental Owners Association of Lane County has a membership of over 1,300+ rental owners, representing over 20,000 rental units(from single family to multi-story complexes). 

On the day I moved in, I found out the property managers had other units in the apartment complex listed on Airbnb because an Airbnb guest tried breaking into the wrong unit (the police were called).

We have a single family home, a small commercial retail building, and now we are pursuing a 5 unit apartment complex.

Quote from @Daniel Stegelman: The apt. complex has unit has six 2 bed 1 baths and two 1 bed 1 baths.

Building a Phase 1-5 messaging campaign is the easy part.I'd recommend you build this yourself, so you can see what's working and what's not, and improve it over time with added features, automations, and complexity.

Could be very helpful I think there could be some good education but these can be fairly complex situations so general advice is probably where this will go..

However, if you feel you don’t need a tax plan that complex, there are tax planners who specialize in working with real estate investors and can help you craft a tailored plan that’s more affordable.

Quote from @Jaycee Greene: Quote from @Zach Matson: I'm doing some diligence on a property that has an existing duplex, but I can build a small apartment complex on the same lot.

Essentially that's what you described doing, but with the added complexity of the auction process.