Looking for further details about what to say to the homeowner to get them to understand the nature of the deal and be okay with it.

It's human nature. 

Good luck, you got natural skills.

You will likely need to provide the following; separate exterior access, fire insulation between units, egress windows in sleeping rooms, minimum natural light area, minimum headroom.   

The Marcellus Shale Natural Gas boom will make Philadelphia the primary source for exporting and importing natural gas, especially as natural gas continues to grow, surpassing coal, as a cleaner and cheaper energy source.

I am definitely not somebody to do something impulsive, so I am setting my goal as to purchase a property by the end of the year more as a way to check my natural over-analysis than to satisfy a need to do it now.

In my market, it's all natural gas, so it gets expensive to re-pipe in order to handle the higher BTU if the existing location isn't near a larger gas line already...

I'm naturally extremely impatient so that's fine for now.   

There are groups out there that offer mentoring and things of that nature.  

Granted, this would vary depending on the nature of the repair.... but lets use the most simplest of repairs....caulking a shower and replacing a board on the deck.