Honestly you’re blowing smoke just come clean so you don’t ruin the rest of whatever credibility remains 

I have a Google Form that I'm using for initial screenings that ask four of our biggest questions (smoking, income, etc.) but I'm not sure where to go from there.

@Matt McGuire what's the lease say about smoking?

Thanks, and, Holy smoke, yes on the lessons learned part. 

Especially if you could go find a smoking deal! 

@Mike Kirby Likely incense or low quality candles that produce too much smoke .

I am 100% no pets, 100% no smoking anywhere on my property...It makes picking a tenants easier. 

Could be as small as a dead battery in a smoke detector in the middle of the night (no guest wants to hear beeping while they are trying to sleep), guests can get rowdy and disturb neighbors, I have even had guests that insisted upon having someone meet them face to face when they arrive.

I recently visited a multifamily property with over 210 units and one of the main issues was the smell of smoke in the units.

Get a smoke alarm connected directly to the furnace 3.