I think they are struggling and throwing spaghetti at a wall hoping something sticks.  

In Mass, that means that all components are double-wall, non-corrosive (fiberglass). 

It is an older home, and would be hard to move walls around to make space without basically taking the whole house apart.

I have 2 rental properties on Long Island, NY and they're both located in the same town.Property #1-Legal 2-family duplex (2 units)-Does not need to be owner-occupied since it’s a legal 2-family-Has active rental permit with the townProperty #2-Single family house w/accessory apartment (2 units + illegal basement apartment)-I live in the upstairs unit-Needs to be owner-occupied in order to get rental permit for the 2nd unit since it’s not a legal 2-family-No scenario where the basement apartment will ever be legalMy family has been renting this house without a rental permit for several decades without any issue.

Is the membrane secured to the parapet wall correctly?

They were popular because they were cheap, since your walls were also your roof.

. $30K should be more than enough for fresh paint and flooring and some other odds and ends, but if you need dry wall, cabinets, countertops, mechanicals etc it could get much pricier. 

I would have to replumb, run new electic, studs for walls, build a fire escape and so on.

The tenants sent one picture of a spec of mold on the wall and that was it.

It demanded to replace full flooring, scrape walls and repaint costing entire year worth of rent from that unit.Question: are there technical solutions inexpensive to remove cat urine instead of replacing all wood , carpet and walls?