Fire damage is tricky.

I am considering buying the property in cash then hiring Servpro to fix the cigarette damage.

I would immediately send a certified letter to get rid of the cats and state the damage that is already done.

Anything the size of a plastic wall anchor or smaller, you should be hitting it with lightweight spackle and use a damp sponge, not a sanding sponge, to take off the excess.

Quote from @Alex Tang: One of my rentals was heavily damaged by a fire after Thanksgiving. 

On the disclosure form, the seller had indicated “no” to any known damages.

I expect that I may have excessive damage on this home as well. 

Maybe they would/could take it upon themselves to pay for the repairs to the roof to salvage your unit and prevent further damage then they would go after the HOA to recoup costs.

How do you believe they damaged this door seal?

The house is a new construction in a Class C neighborhood.The tenants pay late rate ~50% of time, they damaged part of the garage, they have people not of the lease living there, and they leave trash in the yard.Part of me wants to keep these tenants because:-They do pay eventually-I don't want vacancy-The turnover costs could/will be high-How much more damage could they do?