What about other causes/accidents like fire or tree falling, etc …, assuming no foul play or crime?

The odor won't pass through the water.

(As a flipper, I assume you're connected with a local mortgage broker who can fix the foul-ups that come with buyers using depository banks and internet lenders.

The problem is the whole home has an extremely strong cat urine odor.

Gouged, badly worn hardwood floors, missing and damaged window treatments, window screens, light fixtures, holes in walls, screen door, pet odor, waste etc.

She was still trying to scam me by calling me 7:30 am Saturday morning saying she smelled foul smell from attic (we had rodent issues back in March which I already paid a rodent company came taking care of it).  

The bedrooms had carpet in them that had a profound pet odor.

I don't believe any of the repairs that were/are needed are due to the tenants breaking things, my repairmen would have told me if they had thought foul play was the reason the repairs were needed. 

You need to neutralize the urine to remove the odor and sanitize it as well since there were pests there doing their business.

After a recent visit, as soon as I walked into the house, the house has a strong odor of dog urine.