Selecting/analysing overlapping points/lines of adjacent rectangles

I am playing with a definition to visualise different code/setback scenario's in urban design.

In the attached image I have 6 lots/plots and I want to be able to analyse each of the rectangles to set up rules according to edges/frontages etc. To do this I need to be able to determine front and back, where front is the side with only one line/curve along it. A corner would be a rectangle with 2 sides with only 1 line on each.

With my limited knowledge the best I have been able to do is to use an intersection set to find overlapping points, but how can I do this if I have multiple inputs (eg. more than 2)?

Or is there a way that I can find lines/edges that overlap?

Thanks in advance for your help.