(of course it's as far as you know).Might there be a smoker in the property that lived there a long time ago?

We are going to use this property as a house hack and we fully intend to terminate both agreements due to both being smokers and having 6 dogs between the two.

I would exclude them as a smoker.

You cannot deny them based on a multitude of things, such as familial status or sexual orientation, but you can absolutely deny them based on them having a prior eviction, being smokers, not meeting your criteria like too-low credit score. 

Its best to remove smokers of anything, because most smokers are dead in the head, and have no clue or care where that stench goes.If there IS a lease, perhaps you can ask them to leave without a penalty for breaking it.Nope, not anti pot.

As long as you get paid, don't worry too much about how the payment arrived.5) No one wants to live in an ex-smokers house. 100% put this policy in the lease.

Our tenants cannot be smokers (it is not a protected class). 

It wasn't in bad shape, the owner was a non-smoker with no animals and had help come in to clean.

Most companies don't allow them to get a better rating than Standard Non-Smoker, and it's not optimized the way they should be. 

I’ve had more problems with closet smokers than with pet owners.