Verifying last 2 years of rental history very important!

If they have no assets or if you don't have verifiable proof a lawsuit is worthless.

Physically verify everything.

I Offered it to them at 10% below market with him paying utilities. he wanted it, so I screened him to verify he can afford it.

The first thing prior to this would be to verify this is a good tenant, check the lease, and confirm with the owner with a payment ledger that they have been paying on time since they have been there. 

It was pretty simple did you have it verified by an attorney or the ones on apartments.com are already verified?

The fact that you already have multiple units fully rented is a big plus.If I were analyzing this, I’d start by verifying each cottage’s rental history, condition, and potential for adding more units or amenities.

She took about two months studying outreach particular niche and instituted a program in steps where the results could be verified before implementing the next step.  

However the tenant may lie and Zillow doesn't verify much so another application may look great. 

@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.