In one of the better scenarios, a sloping floor could just be caused by something as basic as improper installation of the flooring.

If there is a hailstorm, as a landlord do you reach out to your tenant and ask if everything is ok? Or assume it is if they don’t reach out?

I would assume young, not-yet-trained pets would cause more damage as well (I've not had any of those yet, but I've had my own puppies)But here's the thing, too - young kids probably cause more damage than most pets.To answer your questions:- I don't think there are any laws against discrimination against pets? 

I own a single family property with tenants, and this past year I poured a lot of money into the property after I had family cause a lot of damage to it.

The tenant though has to give compensation and not cause damage beyond excess normal wear and tear. 

If you’re gonna sub anything out it’d be electric, cause you can die doing it lol.

Without even knowing the exact demographics of the income or crime in the neighborhood that could cause it to be a risky investment, the median price of sale in this neighborhood of Mill Hill is 29.5k.

However, I wanted to get insight as what problems this may cause in the long-term (if any) once the current global situation is resolved. 

Furthermore, the town resident who reported this to my mother describes the neighbor as confrontational, known for fistfights and causing problems and has sued people in the neighborhood for other things.  

You could have thrown a bandaid on it and reglazed the tub at your desired cost only to discover that leak that caused the rotted floor would have resulted in the tub coming out next year. possible structure repair and maybe ceiling repair of the floor below with a new tub install and repair cost similar to what you are looking at now.