(Recording a land contract is a mistake in and of itself in my opinion)  Before Dodd-Frank I prepared a few land contracts for client's but have not since as I didn't do enough of them to make it viable for me to get up to speed on the D-F statute and regulations.  

If the statute of limitations is 12 months to bring suit, I would ask the title company why they are insisting on a 15 year time frame.

It says "last known address," in the statutes.

To add to what @David Krulac wrote, the Landlord and the Tenant Act of 1951 is the main statute that governs the landlord and tenant relationship in Pennsylvania. 

Note that the statute contains no significant defenses for well-meaning sellers who thought they were giving the buyer a good deal, even if the whole arrangement was the buyer’s idea in the first place.

Otherwise, you're in violation of RE statutes.

Many of the rules and regulations for tax liens in AL are on this website. http://revenue.alabama.gov/advalorem/index.cfmThere is a section that explains how it works with delinquent taxes and part of the state statute as well. 

Either way: I would work to find some solution because ongoing problems take all the fun out of rental properties:) BTW-whatever your choice make sure you are within your state statutes.

This article summarizes some key Pennsylvania Landlord-Tenant Laws applicable to residential rental units.The Official State Statutes and other reputable municipal sources were used to research this information.

Also make sure to get contractors liability coverage, as you could now have a product defect claim for up to 8 years (I believe that is the statute of repose in CA)