as Bill Gulley eloquently states, when you have an option to buy and record it and then have somebody pay to release your option for a fee is a different animal than assigning the option for fee@Bill Gulley

I own SFR rentals, but mobile homes seem to be a completely different animal.

I have had some damage from pets, but that was from animals owned by tenants that existed before i owned the bldg and, i did have one unit (3 tenants) all claim emotional support animals (3 of them!

X amount per additional animal?

There was a movie called "Animal House" - crazy frathouse  behavior - that is one explanation.

Have you decided that you want the extra expenses that animals will add to your rentals?

This is the California law regarding service animals:http://www.disabilityrightsca.org/pubs/548301.pdfAn emotional support animal doesn't have to be a dog. 

Other reasonable accommodations to consider would be visual doorbells, visual smoke/CO detectors, and allowing hearing assistance animals.

I name the pets allowed in the lease.You cannot restrict service animals and this gets sticky in the case of "companion" animals for those with a disability.

Specifically the unsanitary smell and amount of animal waste improperly disposed of and on the floors.Please be aware that the condition of your apartment is unacceptable and unsanitary for not only you but your animals as well.