The neighborhood was super rough around the edges but I loved the convenience of the location and it was all the space I needed as a single person with a few animals and the occasional room-mate.

Hi Ajay,A building that is 129 years old is definitely a different kind of animal.  

Dead people don't care.Properties don't automatically go into probate, either.Someone has to has some level of standing to file the petition and pay the filing fees.There may be no heirs that are easily recognized, bug there is no such animal as "no heirs."

burst pipes  does it get cold enough to freeze2. mold3. animal fece's4. vandalism damagethese are the common ones when I have bought courthouse steps houses I could not get into .. but there was very few houses I could not get into.. if they were vacant we simply broke in

I myself live in a 100 year old home - and i am sure there is lead paint under 10 coats of paint somewhere.I would really love to hear about what these inspections are like.

I understand as a landlord owning (1) 3bd/1bath/1500 sq ft unit and not using a property management company, I am exempt from many requirements, such as allowing service animals in some cases.Does this also apply to the (2) per bedroom occupancy standards?

The fines should go to the owner of the animal not the owner of the property.

Call animal control/city/past owner and have them pay for it.

As for occupancy it has had to have been empty at some point in time, so that would feel to me like he's already sugar coating it.You can ask for copies of all the leases to see what they say about change of ownership and their rent.  

Use TSP on the walls and if the ceiling is textured spray 3-4 coats of primer over them and maybe some white ceiling paint if that won't cover it up.