at 75 years old, hopefully they've been replaced with PVC, but you have to check.Look at the electrical panel....are there GFCIs, ArcFault breakers, new panel, where is the panel, are the plugs grounded? 

On exterior walls, look for signs of water damage and any major cracks.For electrical, mainly look out for old knob and tube wiring, fuse boxes for the electrical panel, and if it's a regular panel with circuit breakers open it up and see if there's any space left to add onto it, say if you want to add a dishwasher or need it for something else in the future. 

Also check the breaker box.

And that 1 year thing on a commercial loan is an absolutely deal breaker. 

Currently, power is on but lightning blew a couple of breaker switches plus WiFi is down, modem is fried, dishwasher doesn’t work, dryer turns on but doesn’t heat, garage door opener doesn’t work and one Nest thermostat was fried. 

Currently, power is on but lightning blew a couple of breaker switches plus WiFi is down, modem is fried, dishwasher doesn’t work, dryer turns on but doesn’t heat, garage door opener doesn’t work and one Nest thermostat was fried. 

(Most if not nearly all hoa associations don’t allow it in SE Florida due to spring breakers) Hope that helps a bit !

Is a nearby barking dog a deal breaker for people Airbnb-ing this spot? 

There are some portable cleaners that heat to higher temperatures, but they often come with two power cords, because they need two power circuits to reach the high temperature and provide suction.  2.

That would likely be cheaper than taking out the entire slab.Doweling into the existing foundation is likely the proper thing to do along with some bond breaker where it is concrete on concrete.