So we want to make an offer on a house in our target area but it has brown stained walls and popcorn ceiling and a sting odor of smoke.

Abating the odor (tobacco and Marijuana) is costly and time consuming. 

This is the rule where I worry someone could run a foul.  

That will bring odors and accidents.

There is some damage to the home (broken doors, nails and holes in wall, bad odor due to not cleaning (and cats I assume), and destroyed carpets. 

my grandmothers friend decided to go with them, and the gentleman Marcus used foul language with my grandmothers friend, told her she will never amount to nothing, used the F word and the list goes on. this happened last week!!.

I had a tenant call and say that the water from the kitchen faucet tasted weird and had an odor.

Are there bad odors?

The agent also mentioned that there is also the question of foul play that may come up, such as a scam.  

With the the specifics provided it now looks like a good probability that foul play was (is) involved.