Good to take photos so you can compare and if anyone does come back you can show that over X period of time you were at the home and nothing changed from week to week.You can be aggressive on this or less than aggressive, but good to learn your local laws and what is required to do to help you determined if it is indeed abandoned.  

Any contractor recommendations to assist with determining rehab costs for these properties would also be extremely helpful.

And how will we determine the cost for rehab if we've never been to the property in the first place 

I would not personally let age be the determining factor on whether or not you should invest in a property.

Using Listsource I determined that the zip code area 14609, 14624, and 14612 had the most absentee owners within the past six months.

So, first step would be determining why exactly he is trying to offload just this one.

Pick one niche (STR, MFR, SFR) and learn the different types of financing, how to manage them, what metrics you'll use to determine success, and on and on.

I know the owner (not friendly), so my preference would be to await the tax auction.I've reached out to the county to determine if there are issues with scraping a home with its history (hazmat?)

I said, we don't really know, but there was porno glued all over the walls and some of these cuts here and there.

Also, if you were going to do an exchange, you would have had to determine that upfront from the sale of the REIT and use an intermediary.