What are you currently building at price / SQ FT in CHS? 

Fannie Mae and Freddie Mac will not call any areas that are even one inch below grade on any side, square footage.

These 3 islands are super popular with different groups - Avalon & Stone Harbor are ritzy, OC is a little more family oriented, SIC is popular with younger people - and even though about every inch of every island is built out there's nowhere near enough supply for everyone that wants to stay in the summer.

Second, the pipe 1,6,12,24 inches away from the current leak is exactly the same age and could easily leak the day after they finish the first repair.

For example: A 10 wide x 20 deep x 8 tall unit, with studs, roll up door and doorjambs; is really 9 wide x 19 ft 6 inch deep x 7 ½ foot tall.

As an anecdotal example, my wife and I bought our home in CHS a few years ago for mid-$300k.

Tenants have a lease and new owner must abide by it regarding these tenants - sounds like you are turning a blind eye but just remember give them an inch and they will take a mile. 

Usually I'll install 4 or 5, 4 inch lights (3000-3500 lumens) in a kitchen so if one goes bad it's not an emergency.

The house needs a roof and the existing roof is very old asphalt over cedar shake so according to the roofers they need to completely remove everything down to the rafters and install 5/8th inch plywood then reroof from there (one estimate so far came in at $31k for that).  

The first red flag I encountered was when I tried opening the front door, it was being blocked by some object and could only open about 6 inches.