Also, I'd lease out the other bedrooms for additional income as well as practice screening, leasing, and interpersonal comms.  

From my point of view for event guest screening and security deposits, Superhog is reliable and integrates well for STRs and events, but you might need to adjust its setup for your use case.

I do agree $100k revenue on $500k cabin seems should have positive coc, but the size ($7k allocated maint/cap ex which is unscheduled maintenance - annual fire prep has own allocation), delivered propane, expensive utilities, & expensive cleaning take their toll. 

I ended up buying a SFH home on a nice-sized lot and I am building an ADU on the property.

You'll most likely find your staffing costs to be in the neighborhood of $1,200 to $1,900 per unit per year, depending on property size, class, and market. 

This is not a once size fits all question IMO.

It does not matter the size of the city. 

I think that would work if the two units were the same size. 

I have an opportunity to purchase a 2019 built 6 bed/6 bath 3300 sqft (Pool/spa, media room, full size garage) fully furnished STR in Encore Reunion community @ 180 per sqft costs me 600k.

I have thought about reaching out to cash buyers who have a decent sized portfolio about possibly managing their STR/MTR homes.