I got the owners to agree to pay for a new water heater for the building (about $4000), and $10,000 of seller paid closing costs.

Arguing never works.Get a good attorney that specializes in landlord/tenant law and accept that it will at times cost money to have them deal with things.

I've heard Stessa and Buildium for the most part but find it's actually very difficult to use for the average small scale landlord (I have 7 doors)The cost of Buildium I think is way too high for the small scale self managed landlord like myself. 7 units comes to $55/monthAs for Stella, the UI isnt the greatest and probably tailored for more property management companies, and the accounting features are rather lacking for Canadian tax laws.

What did it cost you in time and money to find those deals?

Some people are not ok with this.To get started in notes, there is a learning curve and upfront costs.

You'll have to balance cost vs features!

There will certainly be buyers interested in having an ADU but I'm not sure they will be able to pay for the cost the original owner incurred to get the ADU.

Targeting, impressions, reach have been successful with Cost Per Results.

The one I am used to using provides cost estimates of various rehab products based on specs about the house.

The cost of QuickBooks online doesn't justify our usage.