I don't recommend jumping into this world if you have no experience in the industry.4.

There are no existing structures on the land—it’s a vacant lot.  

Consider getting a statement signed by all parties which states that everyone has agreed to terminate the current lease early on X date and all obligations by all parties have been paid in full and that the deposit will be kept by the landlord and will be applied to the new lease. 

Assuming this is a clean file, with no exceptions required, most Underwriters take anywhere from 48-72 hours to review a loan and get CTC, or provide further conditions. 

If you buy a hot water heater for the other unit, you can write off 100% because you have no personal use of that hot water heater. etc.

We both have good credit but my lender made it seem like there was no getting around putting less than 25% down on an investment property.

I'm no Facebook expert.

Quote from @Louis Hamilton: The property is worth around 800,000 and has no mortgage on it.

I had no idea what to do.

No tax so far I think.2) If I convert that partnership interest into shares in a PUBLICLY traded UPREIT I trigger tax on the deemed sale/exchange of the partnership interest into stock of the REIT?