Such as unplugging smoke detectors, flushing things down toilet not meant for the toilet, etc...

Often I can smell scents from the lower unit that aren't pleasant (cooking, smoking, etc).

There's currently a tenant in the house (who I presume caused the smoke damage), but the seller promises that this tenant will be gone before closing.

Are they smoking outside?

Security Deposit: 2600Lease states no smoking/painting walls/no hanging things on wallsTenants have moved out and have left two truck loads of garbage to be removed.Damaged doorPainted walls which got on the ceiling and trim Lots of holes on the walls throughout the houseDamage from windows being left open constantly Weed was clearly smoked in the house (smell throughout the place) so we need to deep cleanWater bill wasn't paid so I had to turn back on utilityMissing keyQuoted costs:$450 junk removal (some furniture)$935 for damaged doors/windows, painting cleaning$30 for utility turn onTenants were only there for a year before moving out so a lot of this is beyond normal wear and tear. 

There were lease violations disrespecting the other neighbor's leased space and harassing the other neighbor and they smoked in the property against lease, lied about conversations, has made up stories about plumbing issues that plumbers couldn't find causes to, tried to get a dehumidifier and force me to pay, accused me on two different occasions very agressively in regards to the heat/electric service.

Licensed contractors supply materials and subsequently warranties.Also how would a flipper comply with assembly bill 968 if they supply materials? 

Provide the supplies.

So I supply the locks, linen and towels.

Just clearly state that you supply a starter supply of listed items and you should be fine.