I am eyeballing my first Air B & B in Fox Lake, or neighboring town, on the Chain O'Lakes.

Will you rent through Air BnB?

There will be some holes in the wall where they open it up to let air in and dry it out.

I have a unit where the air conditioning is out and it is extremely hot.

you are putting a lot more pressure on everything else - appreciation, capex - when you have financing charges. 

You might find this 20 minute read and breakdown of supply, demand, interest rates, and relative regional pressures on multifamily https://www.biggerpockets.com/blog/multifamily-crash-to-cont...

It's the visual thing for some people mostly, with such small wall space having it right there in your face isn't ideal. when at all possible, every flip will just get duct work and standard air conditioning. 

Are you going to pay your rent, or skip rent and book an Air B&B? 

But all well maintained with central heat and air.  5 of the 7 were vacant.

Do a Google search of air conditioning blogs or news articles.