Purchase the real estate in an LLC to reduce the chances you are personally listed in a claim but most importantly understand the risks most likely to impact your real estate business and take the proactive steps on a daily basis to prevent those liability event from occurring. 

I assume any/all water has been cleaned up to prevent mold/warping. 

Prevents open-ended rent increases while maintaining accountability for pet-related upkeep. 17.3(a) Landlord may 'enter and remove Resident… by force or otherwise.'

We built our current home with my husband being the GC and are interested in potentially building to sell, but am not sure about capital gains and other fees etc that would prevent us from making a profit from it.

But a couple of thoughts come to mind:1 - An ounce of prevention is worth a pound of cure.

Hey guys, looking to do some preventative maintenance and have my electric water heater replaced.  

Thus, for example, placing your FL property into an LLC can help prevent any lawsuits or creditors associated with that FL property from exposing your personal assets such as your home.Outside asset protection on the other hand, works the opposite way by preventing liabilities coming from outside the LLC from exposing the asset inside the LLC.

Another thing they told me was that the coil should be cleaned every 2-3 years to prevent this sort of problem ($150 or so).

Create a big picture list of what is needed, your goals, and then get granular of what needs to happen now and then create a schedule which each day after closing, what needs to be done, who will do it, how much it will cost, and who will verify it was done to standard.In short, even if someone were able to answer your question with accuracy, it would do you no good. it would only prevent you from focusing on what you can control.

When you have questions feel free to reach out to the experts its better to have the knowledge prior to the mistakes and use preventive maintenance.