so the question is can you charge more ..no, requesting any documentation is questionable in many forms, even that form asks for some info that a dr can not answer such as the particular dog weight etc, the patient is all the dr can certify to and ADA doesn't allow requests for medical records, the  tenant is in, leave it be unless you are having a problem then address the problem, service or emotional support animals can not be disturbing or aggressive but no there is no legal limit number and can have an animal for each disability if needed, double that if more than one disabled occupying,  the added insurance expense has been addressed and too bad , added damage should be treated as if it done by tenant not the disabled persons appliance(dog) and can not be more than normal wear and tear, just require they are properly licensed by local laws which will require shots etc all service dogs must follow that and undercontrol no roaming outsideyou got the property with the tenants in and the dogs, status quo generally wins out

Being that the building is over 100 years old, i.e. prior to the 1992 ADA, what ADA/FHA access provisions am I required to supply?

We didn't know that the city didn't like those plans (Mistake #2).The contractor eventually was in over his skis between having to increase the diameter of the public sewer line to ADA compliance to the required indoor sprinkler systems, so a few weeks after closing on the property, he had to walk away from the project.As we scrambled to find a new contractor and to get our plans approved by the city, our holding and soft costs ballooned. 

They have coatings you can get that makes the tub less slippery.They have ADA type handrails you can install.They make slip resistant flooring. 

Regarding ESA (emotional support animals), I find it frustrating that the FHA and ADA differ on whether ESAs must be accepted or not by landlords.

If there is a legitimate disability, the ADA may apply. 

I imagine the ADA, Fair Housing laws or HUD would provide some guidance.

Here is an article addressing the ADA compliance. https://adata.org/faq/how-can-... 

Taxes, insurance, fire, ADA, EPA, etc. 

I read on the ADA site but could not find that detail. thanks in advance