Often the Ada County Assessor is not using accurate comps and its good to know so you don't walk into the Board of Equalization Meeting blindsided. 

Each law uses the terms "service animal" and "emotional support animal" but actually defines them differently.Would a short term rental then, which is providing a service akin to a hotel, be governed by ADA or FHA?

If the property is grandfathered in for ADA compliance or other requirements (elevators, handicap ramps, etc..).  

I know it's a rather long ad, but were you able to read those parts of the ad as well?"

They might ask about ADA compliance, number of parking stalls, designated Handicap parking, do you have grandfathered in fire suppression, etc.  

Making one apartment ADA, creating another form of egress,  upgrading the insulation to the required r value the list goes on.

He stressed the importance of it being ADA accessible so larger bathrooms and specific ADA Standards, but they pay more. 

There are quite a few nuances, but much of this is covered under Federal Fair Housing law and the ADA.

@Steven Medaglia if they’re a good tenant I would allow the mother to move in and add her to the lease.In accordance with the ADA (Americans with disabilities act) you MUST accommodate their request to modify the property for handicap accessibility but you do not have to pay for it and can require them to return the property in its original condition when they leave all at their own expense.Good idea on the licensed contractor part.

You will probably need to look at Commercial policies (Business Owners or Package policy).Another consideration is the ADA compliant changes that are required for that use.