I was thinking of doing half and using the other money for a gazebo/ with grill and dog park. 

There were smokers in both units when I purchased the property and I well remember the time and effort it took to clean and repair the smoke damage.

I just won't deal with smokers anymore. 

Warren Currier is a rental owner in Boston that may offer some help with this if you reach out to him.All smokers say they won't smoke in the house.

It is similar to a cook at a popular restaurant buying meat, but cooking it on the company grills, using the waitresses to serve it out the back door to customer pulling up paying cash.

Sadly, I never really took the time to learn from her, so I've started this process with no expertise.Honestly, I've been lurking on forums, reading blog posts/books, and grilling coworkers with portfolios, trying to piece together something approaching a business plan for a few months now.

At least she destroyed her grill in the process.....

If the prospective tenants are smokers, the landlord does not want to allow any smoking in the apartment.

We call this kind of fire a “smoker”,  not a lot of structural damage but a lot of damage because of smoke.  

Having dealt with smokers who dont think butts are trash and twenty something slobs I empathise, your best bet is get them out.