Immaculate condition, almost everything new, including kitchens and baths, all new replacement windows, hardwood floors professionally refinished with 4 coats of oil based polyurethane,all new wiring and electrical panels (all knob and tube eliminated), new plumbing and washer dryer hook ups in each apartment, new interior and exterior paint 2014/2015, newer cast iron boilers, 1st floor has additional natural gas fired high efficiency Rinnai direct vent wall furnace, State and local fire code compliant with all new 90 minute fire doors and modern whole house fire detection system.

We are definitely planning an inspection; do you think mold/ moisture issues would be detected even if they are covered  up like this?

If he's serious about selling the property, he could pay for a detective or you could talk him into a way better deal if you do all the legal work.  

So, again, while I appreciate all the thoughts, what I'm looking for is a recommendation for a smoke detector that detects cigarette smoke and either transmits a notice by WiFi or keeps a record that can be used to support an eviction.

Again, THEY are the ones insuring clean title so they'll make sure that stuff is dialed in.5) If later on something came up that title missed, as unlikely as that is (I've done $100m in deals, never had a title issue), that's what title insurance is for.At this point there is no need to waste your time playing detective. 

To help us monitor your compliance with our house rules, we use a signal detection sensor in our home that will send us reports regarding (fill in what ever is needed here)  the total number of devices in our home at any one time. 

All of the major systems in the home (HVAC, roof, decks/porches, windows, fire detection system, etc) have been replaced in the last 5 years so if the people know what they are looking at they should realize what the property has going for it and anything the units need done is cosmetic stuff that will be done on unit turnarounds anyway. 

PLEASE PASS THE WORD ON AS THIS DANGEROUS FRAUD IS NOT EASY TO DETECT IF YOU ARE NOT EXPERIENCED.

For example, I have had people tell me that there is a member of their family with severe asthma and if I can detect any odors ...

Or perhaps trying to detect any potential problems with the property?