Keep in mind you should still account for maintenance, capital expenses and future improvements (which are all accounted for in commercial property along with vacancy factor)I know this is a lot of information but success is in the details.Final point, if the numbers are right this property should qualify for rehab and long term financing.

So if historically the area has been renting in the 900-950 range but now inventory is low, you may be able to get higher rents and therefore actually cash-flow (if you had the whole thing rented). 

We'd each contribute equal capital into the partnership, but our competitive advantage is that he'll live near our properties, is an extremely skilled contractor, and can thus manage and repair/improve our properties more affordably.

Essentially, there must be a paid parking footprint in the area already.The ideal asset would cashflow from day one with the ability to add value via technology, operations improvements, and/or NN lease addition (or renegotiation).

Specific home improvements that are more expensive such as home extensions, new landscaping/pool, and backyard upgrades should be looked at as long-term projects that will help you get more value when you are ready to exit.

Are you looking to cash flow or improve tenants/rent and then resell? 

I am having trouble understanding how to appropriately evaluate the property's value - is it based on the current "market" value, the 2020 tax assessment value of land and improvements, or from a bank appraiser who would be used during the purchasing process?

Inventory is at .8 months last time I checked.  

They can help identify good neighborhoods from bad, identify potential problems the property may have(such as neighborhoods that may have subsidence issues), identify improving areas, and have a list of competent contractors and inspectors.

Based on the market and the improvements I would bet the property has increased significantly in value.