I agree with not getting too intrusive.  

It may be a way to differentiate yourself, but seems like it would add a lot of cost, and could also be viewed as intrusive.  

I am still trying to determine feasibility.Roof- All four need new roofs with all units showing signs of water intrusion. 2 units have full ceiling cracks with sagging.Aesthetics- Needs a complete makeover (lipstick on a pig).

Lack of MVOC can point to dormant mold as easily as it points to lack of mold.Based on your description, I'd say you have visible but inactive mold present, a serious water intrusion issue, and to run like hell unless you have the money to hire a professional mold remediation firm to test, correct your moisture issue, dry, remediate, clean, and retest.

There are probably engineering reports and evidence that the building is leaking and has water intrusion which is what prompted them to file suit.

Finding one shut-off valve for over fifty townhouses hampered our swift reduction of water intrusion.

Separate entrance would make it less intrusive on them.

If investing in real estate rentals is your ONLY source of income, thats where I can see the question of "how many units do you have" being an intrusive personal question for some people.

Also, active water intrusion is typically a code violation so you could have trouble re-selling it if it remains unresolved.

I have a window well that doesn't have a cover on it and I want to keep water out of the window well. When we had a storm the other week, I had some water seep in because of how fast the rain came down (first time in ...