Your DD should be pretty straightforward, but really look at the developers success, what other projects they have or this this it, and obviously how the contracts and ownership is documented. Who owns the assets? What kind of status updates will they give you (monthly) and how can you audit it? Is your only return on sale of asset to rent? What is your pref and when is it pages? Make sure your principal is relayed first, then pref, then ownership equity.
It's really the same as any investment. How can you lose and how do you keep that from happening.