@Steve Nowak is correct.The condos likely have a level of insurance that they require you to carry.Your policy should cover damage to common area and adjoining condos in the event damage is due to your (tenant's) negligence. 

PM kept telling me its the ex-PM negligence.

If it is tenant negligence, I wouldn't replace her food.

If tenant negligence caused the infestation, then I would bill the tenant for some of the costs.Do your best to make sure exclusion of rodents is done properly and thoroughly.

I manage and maintain the properties myself, so the other two costs are negligible.

The cost to setup an LLC is $155 so the cost is negligible in the grand scheme of things. 

I much rather have a tenant who will let me know when something is up rather than open the door after they've moved out and find that I've got 5k worth of work as a result of tenant negligence.

The title insurer will deal with the title company's negligence and will pursue the borrower for unjust enrichment.  

Property #2. 15 mins is negligible travel time.

1-3, 4-7, 1 pack or more, none - I will not allow anyone who indicates that they smoke to rent from me even if they say they will smoke outside (they will smoke inside once it gets cold), turning a smokers unit is very costly once they leave, and you could incur fire damage from negligent smokers on the interior or exterior of your property - a week ago a tenant caused 10-15k worth of damage on a porch at one of my duplexes7.