Upon reviewing the p&s we noticed that tenant A's lease term was changed to expire in May 2019.

Change it or inforce it.

My lease states The only person(s) living in the Leased Premises is/are: (the husband & wife)  A.Any change in the occupancy will require written consent of the Landlord and may be subject to an adjustment in the amount of rent. 

Property taxes are evaluated each year and will likely change in 2019, but not when you purchase the property.

Ask your insurer to add or take things away and you'll see how the numbers change.

I wanted to do minor cosmetic repairs such as changing carpets, painting, and new cabinets (new cabinets were needed), and new appliances because they were needed as well.

Without changing the price.

It is also changing all the time as there are so many more tenants than LLs and politicians are hungry for votes and attention. 

I have rented to up to 3 roommates, and the constant changes, due to arguments, job changes etc. always resulted in problems.

For future reference you should have estoppel forms filled out by current tenants as well as a clause in the contract that the owner will not make any changes to leases or admit new tenants after the contract is signed.You could check your insurance policy to see if pit bulls is against the policy in which case you could give them notice that it violates your insurance and they have 30 days to cure or move out.