Depends on your approach and exposure to liability.  

@Dallas Trufyn  I'm not sure these add any value as both the fire pit and grill are fully portable and I'm not sure if anyone would assume they stay with the property upon the tenants vacating.The looming issues here are the failure of these tenants to abide by the lease terms, and the exposure to liability they have just generated for the owners.  

It has a huge exposure to potential tenants and their agents. 

It will make the room more comfortable but windows can be expensive.I am a big fan of solar depending on where you live and how much sun exposure your roof gets. 

Meanwhile, you still get exposure to the intricacies of larger deals. 

The exposure to the busy street means you will probably need to actively keep an eye on it compared to other properties.The first thing I would do is look at zoning to see if there are any readily apparent issues right off the bat.

It can also help with exposure to new thoughts, industry knwoledge, etc.

Limiting your personal exposure is a smart idea.

I often break it down into the "five pillars" of protecting your assets.1st pillar is avoiding unnecessary and risky activities (don't drink and drive, insurance generally won’t cover your poor decisions) and take good care of your investments - these simple steps will help you prevent lawsuits before they even occur.2nd pillar is a good insurance policy as that cover the majority of your exposure.

my personal philosophy is to use a carrot approach, rather than just keep their deposit. tell them they can both be held liable for entire contract amount, but if they keep the place clean while you show to prospects and leave the place in good condition it will limit their exposure. of course they should be held liable for any time unit is vacant, but your main goal should be to put new tenants in asap.of course you have the option of taking their deposits and cutting them loose. your approach will depend on state laws and how nice you wanna be.