The house was in rougher shape than it appeared on Zoom and the stairway carpet smelt like money, dog urine.

I hope no matter if you decide to sell or hold on to your property you will be able to get over this hurtle and come back with a package of experience for your future investments. 

I was horrified by how they left the place: pet urine stains and odors on the carpet, which I had to replace.  

Are you managing urine screens and collecting from insurance to do so?

He said that when he went downstairs the cat urine smell was almost unbearable (he has been in the business for 40 years so him saying that means something). 

Just include a clause with a heavy fine for destruction caused by urine.

I'll definitely give that a readOne of my main hurtles is the Fiancing When you take money from the investors and offer them the Yearly return plus selling benifits it could take a year or two to get property up to speed and performing.

Evidence of cats: smell, urine damage, scratching damage on your woodwork and on their furniture, pet hair (look under refrigerator and range and in hvac ducts and filters), broken window blinds, kitty litter box, cat food.... the cat itself! 

You sent him a notice and drew a line in the sand and he urinated on your line .

Hooking up utilities and plumbing would be another hurtle as these permits are not cheap.