Would like something around 1000.No kids, No pets, is single.  

The lease states no pets allowed but it sounds like the owner allowed her two pit bulls.

The dog is friendly when they are around but when we entered the house without them in the past he snarled and showed teeth.

Of course, I screen thoroughly, seldom allow pets, own in a very nice area within a few miles of my home, drive by the homes often, etc.

Can I calculate pet deposit $200 or $25 month pet service in analysis.

Most, are not, in which case you could choose anything random: a part of a sailboat name, a part of a movie name, a pet's name, a childhood memory, a snipet from a quote. 

You did make sure to have them get renter's insurance to reduce your liability if someone slips and falls inside the property, a pet bites or knocks down someone and they are injured?

The second floor apartment was larger, but kept very messy; i.e. pet hair everywhere, spilled food, and the very heavy scent of unwashed clothing/bedding and cat spray (the tenants had 3+ cats in there).

In my area, renting SFRs, not allowing pets would cut my pool of prospective tenants by probably 2/3rds, but not allowing smoking cuts it by maybe 10%.  

Another real cost is holding costs while not being paid and damages to the property--and by damages I don't just mean retaliation, I mean deferred maintainence, pet damages and crazy decorating choices which is what I mean in 3) above...losing control.Also, an owner held mortgage, even seasoned, is not very liquid and if interest rates go up, even less so.