. - Mobile homes are permitted I've verified with the recorded restrictions and by calling the Property Owners Association. - Current owners have surveys, this is a new subdivision.- Public sewer available.- Current owners purchased many lots and they haven't developed them.

Verifying last 2 years of rental history very important!

@Hamidou KeitaTo build a duplex or ADU in Tucson, verify zoning regulations, obtain construction estimates, budget for unexpected costs, research market rent and vacancy rates, calculate ROI, consider neighborhood and property value trends, analyze construction timeline, consider exit strategy, and consider a backup plan.

So, while on the surface it sounds like you are entitled to your money back, a closer look at the contract and circumstances is needed to verify that.

Verifying last 2 years of rental history very important!

@Jay Hinrichs has posted on that in the past.Many people like to try and hide their identity because of the spotlight effect which refers to how people often overestimate how much others notice (or care about) them, effectively inflating their own importance in society. 

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

You just need to verify that. 

We work on the principle trust, but verify.

One of the utilities, South West Gas, based in CA, gave me a hard time putting the account into my own name. after several calls, faxing the court-stamped eviction order, verifying my deed through the County, etc,  the operator finally agreed and started to backdate the account change to the beginning of the process!