Phone rang off the wall starting about 6:15 AM.

One would not have uncovered the issues we are talking about here with any typical inspection unless they actually take down the fans to see it, or if the attic is accessible and they crawl all over it.The typically do my own inspection before purchase and as a rule I open at least one wall box and one ceiling box in each room in the process just to see what I am dealing with. 

As far as smoking specifically, if the lease doesn't prohibit smoking then any smell or wall yellowing cannot really be charged to the tenant.

In the future you may need to either manage yourself if you end up doing so much, or retain a new mgt company.

Or paint a wall, begin hording, add a electric space heater or start growing pot...not long.I tell my tenants it is for their benefit and safety for me to inspect furnace filters, smoke alarms, CO2 alarms etc.I personal am more concerned about my property investment than the minor feelings of tenants.

They all have lawyers on retainer.

Another contractor said cheapest and best option is to do gas wall hung boilers (instant hot water) and baseboard radiators in all 3 units, all mechanicals located witin the units.

Everything from protecting the home to managing the home and tenants in a way that will retain your tenants.

Thoroughly vacuum all nooks and crannies in the room, like where the carpet meets the wall, and follow up with bed bug spray.

Appliances at per hour rate Window cleaning, tracks, at per window rate, A/C filter cleaning / wash it 10.00Bath tub at hourly rate Key replacement, lock replacement, mail box key, remote control.Glass and screen repair as per item Carpet Cleaning extra spot removal, cigarette burns, pet odor Sheetrock repair, nail holes starting at 15.00 per roomNicotine smoke or grease smoked walls, wall wash, kilz primer per room charge, extra for ceilings.Any furniture left per item, list couch 45.00, chair 25.00, mattress 25.00  plus labor to move.