Legal issues and other circumstances have led to my family holding possession of the property despite most of the demolition having already occurred.

This takes a while so you may want to get that started before the 30 days is up.Order a lien sheet to see what bills are due for you to record you deed.Record you deed.If it is occupied you either need to do cash for keys or file for a writ of possession.

You need a judgment to get possession of your property. 

You need to send a Demand for Possession for Non-Payment of Rent.  

It could be argued that since it is vacant no one has possession.

That does not make him a professional tenant, possessed of an entitlement mindset (except insofar as he is in fact entitled to what he paid for), or someone who must be punished as proof the landlord cannot be pushed around (I'm wicked tough, respect my author-i-tie!)

My mother's estate received a judgment against the tenant for monetary damages as well as possession.

That's when the Notice to Quit now becomes a DEMAND FOR POSSESSION e.g.

What owners lease to a tenant is the enjoyment of possession, same rights as the owner has,  if you have the right to play the piano in your home, so does your tenant!

Figure 100 to 200 to file if you do on your own and then more if you need to file for possession (i have never needed to do that yet).