Again, I envision five families working together to cost share a property. 

When you start looking for multi families, you should look in their areas because they will be the lowest cost property management option.Can you tell me more about your Myrtle beach property, how you found it and how your experience has been with it?

You clearly have little knowledge of how to run a business and the costs associated with it.

Look into the cost of this for both partners and all the necessary schedules that will need to be generated . 

We are in the process of flipping our primary home and have found costly repairs that are needed, and we simply cannot come up with the needed funds to pull us through when we list in September.

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.

Legal remedies can get costly.

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