That's my two cents.As always, seek professional advice.

I've written to her and tried to request *address service* on that letter since that same lien hasn't been paid in the last couple of years.I'm guessing my best course is to consult a legal professional but I'm trying to get as much leg work done ahead of time.MY QUESTION: If I'm able to make contact with any of the 'next of kin' for either party, is it possible that one of the parties can claim 'adverse possesion' and claim rights if I cannot get both entities together on the deal?

All rooms have permanent stains from urine and other things in multiple spots that a professional cleaning service could not remove. 

Once again you build a database and get marketing.From here word of mouth will keep you busy unless you do a crap job of course :-).Lastly I have been sent LOTS of clients from the professionals I work with.

Once they lose a case due to procedure, they become bitter and remorseful for not spending the extra money to have it done professionally. 

. , You probably want to get a professional to do this if you are not confident.

Will that be enough to rid the house of bed bugs or will it still require professional treatment?

Philly is a very tenant friendly city, and professional tenants know all of the ins and outs to work it to their advantage.

There are some professionals in the BP community that may also be able to provide the advice you seek. 

As always, seek professional advice.