Be warned - getting a short term rental to market is expensive, stressful, and exhausting.

Guest left all windows and door open in our cabin in -15 degree weather when they left causing a frozen pipe.

For instance, plumbing might be updated but not every pipe. 

Most of our water pipes are in the ceiling here and when one breaks it ruins the floor, plus we have had some flooding and other issues in FL.

Then interview them.Now, let's look at your issues:1) How did replacing a toilet result in a burst pipe and flood?

Is there a pipe leak that is softening the soil anywhere nearby? 

A hole or two (check how many you need.) and some plastic pipe?

Anywhere from $500 - $2500+ depending on the insert you install and whether you run the vent and exhaust up the old flu or cap the flu and vent/exhaust through the side of the house/chimney.If you hire out the entire job, expect to be in the $1K - $1200 range.

Old pipes and lots of lessons learned.

Pipes froze in December and it flooded.