Again I am not a lawyer but my view of the ADA rules is that they do not include ESA animals, cats (or any animal other than dogs and miniature horses) and that most posters have not looked into what ADA states.  

I have found it harder to find someone to build a four-plex because ADA laws come into play.

And if the home is designed with them in mind (ADA compliant bathrooms/kitckens, elevators for a multi-unit, etc.), it just seems like a good way to go.

We were thinking our best option would be to sell on land contract both ad a deal or the house on contract and sell the land next door straight up to someone but to who?

But after considering these other factors (bathrooms, hallways,  ADA compliance), I am concerned that I'm unable to provide what they are asking. 

Department of Justice's publication Frequently Asked Questions about Service Animals and the ADA which are relevant to your situation:Q: Are service-animals-in-training considered service animals under the ADA?

John, I am not a licensed pro but I will share with you some of my thoughts as I'm AD as well and have been through this process a few times.  

Hi.....I seek homes for folks that are wheelchair/ADA/Disability set ups.  

If they have not confirmed an hour prior to their appointment, I send this text to their phone (which was required as part of their contact information I required in the response to my ad):As I had requested in my email, you have not yet confirmed your apartment showing for this evening, scheduled for 7:00pm.

ADA clearly indicates that it must have specialized training and that cats do not qualify.