Renting the lot might be your best option, and to be honest less hassle as well!  

Investment Info:

Single-family residence buy & hold investment.

Purchase price: $800,000

Cash invested: $400,000

Home I rent to a family of five

You might consider cutting your losses and selling it, or investigate STR options.

Once you have self-income, and if you don't have employees, you can set up a Solo 401K (and Solo 401K Roth), the best option of SDIRA options, and contribute tax-deferred/free $69,000 per year (and $69K for your wife, if she's a managing partner in the PM LLC), thus setting aside a big chunk for more investments (private lending, notes, syndications, even more houses).

You of course have to find a deal that will allow you to make the extra money that would pay for that.

There are better options. $3,000.00 is lower than I have heard people say they have paid. $8,800 to 11,000.00 is more realistic because like most guru's they hold back key components unless you pay more for them. 

Pay extra attention to due dates, late fees, pets, guests, and tenant responsibilities

What are the best options within the city limits as a rental strategy?

What are my options to cover the $100k difference to still get this house with 0 down?

Noah, I would call the local officials and ask them for your options.