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

Otherwise, you could potentially do a Debt-Service Coverage Ratio purchase or refinance to get the necessary funds which would be a cashflow based lending option for investments. 

Properties with power lines overhead are great since no one can build underneath them.  

Plenty of free options out there to learn the business and get your feet wet and start taking action. 

But I see my options are 1.

We have several different "types" of properties to include traditional single family rentals, one multifamily rental, lease to buy options with tenants who hope to buy from us, two short term rentals, and some agricultural farm land that is cash rent. 

Option 2: Private LoanIn this option, a promissory note is written for my partner to loan me the down payment amount (20%/$46K) for a 2-5 year term at a 10% interest rate (details are still up for negotiation - are these terms reasonable for this kind of deal?).

Once the home is permitted it will significantly open you up to more lending options without any cuts in value or LTV. 

Specifically, we're exploring whether constructing a duplex and triplex or two duplexes would be the most profitable option.

The buyer definitely owns the property, otherwise it is not owner financing, it is some sort of lease or option or a combination of the two.