2) As a partial year resident, do I just include the resident portion of taxable income in the base, rather than use the non-resident worksheet? 

I meant 10% down based on SD multi-family real estate prices.

Questions I'd have if I were in your shoes would be based around how the CAM expenses, management, taxes etc are going to work. 

An additional benefit of a detailed engineering-based Cost Segregation Study is that it can increase potential insurance premium savings as well as provides support for the property tax appeals process.Additionally, it can help maximize renovations and improvements.A Cost Segregation study is an IRS approved federal income tax tool that increases near term cash flow by utilizing shorter recovery periods for depreciation to accelerate return on investment.

Projected returns based on entry cap may be high but actually making those returns is very tough.

Based on the above projections I receive, I then "run the numbers" to see where I project to end up each month. 

The profit should be split based upon whatever agreement the two of you come up with.It would be unfair for you to put in the majority of sweat equity as well as the training involved to have a 50% profit split.

payment based on performance?

@Donnie N. based on the video:1.

I have heard of a company that I am drawing a blank on that will pay you for a piece of the equity.