It falls apart completely if you think of yourself as as tenant and pay yourself rent (that you would otherwise be paying someone else).https://www.richdad.com/your-house-is-not-an-assetI prefer the quote from The Richest Man in Babylon, "Make of thy dwelling a profitable investment." 

A broader market demand can lead to faster sales and potentially higher profits when it's time to exit the investment.#6 Lower Maintenance Costs:In comparison to small multifamily properties, single-family homes with ADUs often have lower maintenance and repair costs.

Does anyone have recommendations for an STR on-call service (not full property management), which will handle basic guest communication during their stay and handle organizing repairs (i.e. calling a plumber, HVAC, etc. ... not actually doing repairs themselves)?

There simply may not be enough "meat on the bone" to make a profit commensurate with the hassle and stress.

I will only live in one of the units 4 out of the 12 months of the year because the other 8 months I will be with the Angels organization, during that period they provide a place for me to live and also food, so during those 8 months I would have more money I could save up and use in my house hack.

meaning it would have to be making a net profit of at least the 8k to the investor + the 6k to the GP + the other expenses like opex and capex etc each year correct?

It may be more profitable in the short and long term than a duplex. 

I would like to pay a percentage of the sales profit.

The best case deal for us would be to find an investor who is willing to buy the land and do a 10-year (or longer) rent-to-own agreement with us that includes them getting proceeds from the campground and event center and making a great profit over time. 

Increase profits, no.