Outline everyone's roles and responsobilities, address as many likely points of contention up front, and you will be sitting pretty for the duration.  

Will any of these partners be fully passive investors, or will they have an active role in the operation of the deal?

As you said, appreciation is another major factor, odds are that properties appreciate better than in another regions, rent potential are really great in the area as well, what other factors have you seen play a role in property selection?

@Jesse Holshouser I echo Steven's congratulations: you are in a great position which we all aspire to attain.In my opinion, psychology should play no role in these decisions.

I will say for both of your sakes at least create a contract covering as many bases (the ones I keep in mind: Death, Divorce if applicable, and clearly state both parties' roles and responsibilities as well as exit strategies if needed) as possible to make things easier should issues arise.

The most recent national data by Black Knight:http://www.bkfs.com/CorporateInformation/NewsRoom/Pages/20150223.aspx- New York and Colorado see increases despite winter's seasonal effects - New York ends 2014 just 0.6 percent off its pre-crisis peak - Top-performing metros again dominated by Florida - While recovery continues, Arizona and Florida still remain about 30 percent off their pre-crisis peaks

You can make the class tracker whatever applies to your business, but this is how I do mine, just to give an example. 

I would buy as many vacant homes with more than 45 DOM in the Salt Lake valley as I could buy with $15MM, refinance them, rent them out, and use my remaining $5MM to pay the negative carrying costs.However, if I just got to the point where I can afford my cost of living and have zero savings or an emergency fund then there is NO WAY I'd take on a negative carry. 

I see real estate being more like law, psychiatry or medicine, where humanoid professionals will still have a role for the foreseeable future.  

To be clear, the PM's (Account Executive, Community Manager, or whatever title) role IS to provide Guidance, and to execute lawful Policies and strategies of the Board.