Nowadays I’m  referred deals from a fairly deep network I’ve built up, but you can search listings that have been for sale with no offers for a period of time and see if they have an assumable loan.  

Inspect for any rot or damage periodically, and replace or repair sections as needed to maintain its condition.Potential Upgrades / Considerations: Security:Enhance security with robust locks, a video doorbell, and exterior lighting.

I then thought of the idea to offer they a fixed rate if they private lended me cash on a short term (5-10 year) period.

Many listing agreements have a protection or holdover period, which means that if the property sells to someone who was introduced to the property during the listing period, the agent is still entitled to their commission.

Would have a great re-sale potential of about $1.5mm profit on $500k investment over 2 years Cash on Cash plus the rental during that period, plus I've analyzed the market, and it is a solid location with little potential competition that could build.The Country Subdivision has the greatest return with the least amount of input, but the housing market and thus lot sales are a little more questionable, although this is a great location. 

I don't want to be stuck with a massive payment because I can't househack.Thank you in advance for your timeI would give the city a call and get clarification on the zoning before your option period is up.

This past winter i signed a tenant for three months with options to extend monthly until spring summer.

To prevent any future misunderstandings, simply inform them that paying upfront for an extended period is not feasible.

No one that I know of (ever in 33 years) will lend based on the ARV over Cost over that first short period of time. 

@Michael SoukupVA loans are for primary residences with a minimum occupancy period of 12 months.