Hey @Scott Peters -Dry rot is caused by a moisture/water problem ... we see it a lot around sinks and bathtubs/showers. 

Looking at pictures won't tell you if the HVAC works (or how old it is), won't tell you if the water heater is installed correctly (unless the listing includes pictures of the water heater), won't tell you if there are leaks under the sinks, won't tell you if there is evidence of moisture in the basement, won't tell you if there is mold in the attic, etc. 

High quality 'gently used' furniture is the way to go.

When moisture is evaporating up though the slab and ultimately through your grout joints you'll get water soluble minerals that are left behind on the surface of the grout, its called "efflorescence", and yes, its very hard to clean.The only ways to avoid this is to check the subfloor with a moisture meter to be sure it's completely dry or installing a vapor barrier over the slab prior to tile. 

There are a few tricky details that the contractor HAS to get correct to make sure moisture does not become a problem:1) If used for a roof, make sure the roof is built with a cold roof to allow for ventillation.

So the flooring will need to be completely replaced, but the real issue is moisture causing the wood to swell and "pop loose".The left hand wall where the baths are has a higher moisture content along the baseboard, and the wall between the 2 baths also had a high moisture content.

By the time you get rings and deposits, the porcelain is already compromised and etched, so no need to be gentle at that point.

Use a metal one if possible unless if you are very gentle.

It was laid out over a gently sloping hill side with several natural springs.  

These houses are still settling and the engineered works better.LVT for the basement areas due to the moisture issues that can occur.Carpeting the steps from first floor to second does help with noise reduction.