Insulation: If doing a total rehab consider paying the difference to have 4 to 6 inches of spray foam insulation installed in the exterior walls and rafters.

The other company says that due to the anti-microbial spray that has been applied and the drying fans and dehumidifier that are currently running that it is safe for the tenants to be in the house.  

In VA, I paid less than $5k to spray paint an entire 2200 SF interior with drop cloths. 

Most of the time that works unless the cats/dogs have sprayed the walls too - then the drywall has had to come out.

The money is also being used to spray for roaches in both my and the tenant's unit.

The previous owner was a Hoarder and I am sure probably had so much stuff piled up to the ceiling to where if their was any leak to be found, the damage would already be done....there was KILZ sprayed around numerous areas of the property (both bathrooms, kitchen underneath cabinets, in basement area underneath where kitchen is located. 

I called in the professionals and they sprayed as well as baited the area. 

It has been amazing & maintenance free.I recently went to a trade show & they had several booths with much the same product we used so its getting popular & some of them are now applied/sprayed on as a 2-3inch thick walk-on insulating foam impervious to moisture.

I burned through 2 of them trying to spray latex, and it more frustrating than anything. 

@Matthew Soule I haven’t done this but another investor I know said he uses “game cameras” (like game hunting) for surveillance on his properties especially the vacant ones.Another option is Amazon Blink but make sure to get the ones that are rated for outside if you’re going to put them there.Also keep in mind that you may wake up one day to find the cameras smashed or spray painted.That’s a very tough problem if you live in the building.