Take the anticipated rental income, subtract all expenses, and what is left over is yours to keep. 

So, I would really think if this property will really perform as you anticipate before pulling the trigger.

Her first one was profitable, but not as much as she anticipated.

Note holding fees would include property taxes, insurance (if you are doing force placed insurance), and servicing over your anticipated holding period. 

The counter offer was much higher than anticipated with a note saying that they will have to fix any FHA required repairs.

That is not to say there are not plays that do not require a crystal ball close to home there are and they have worked exceptionally well in areas that were once not so great on both your coast and mine but I don't think those are sure things esp. not anymore now that many prices anticipate at least a bit of gentrification.

That said, what didn't pencil was the over-valued land price, the cost of running electric and water hookups for each of the houses over 40 acres, land-clearing and excavation, and the amount we anticipated people would be willing to pay per night extra for glorified camping.  

Where they make 3x (5x combined) I don't anticipate that ability to pay rent would be an issue.Good luck!

Id say ppl in your neck of the woods are listing in anticipation of an interest rate increase.

There is going to be a very very sharp learning curve that will end up costing more time and money than you anticipate (most likely) If your partner believes in you as a person rather than just the deal they will navigate those difficulties with you.