The cracks are areas of tension where the pads are pulling away from each other due to the shrinkage.

Since the marble was installed over a wood sub-floor, which I assume was plywood, the creaking or squeaky sound is probably due to the plywood not being attached properly.

Most Granite slabs are either 3/4″ (2cm) thick or 1.25″ (3cm) thick, and the standards are based on those thicknesses. The thinner the stone the less breaking strength the stone will have.

Depending on the type of natural stone you are trying to match, it can be easy to match or more difficult to match.

First of all you need to determine what kind of tile to install? It needs to be slip resistant, and it needs to provide a relatively flat surface so no one trips. If you are in a freeze thaw area then the tile needs to be freeze thaw stable.

The method you use to re-polish a tile surface depends on what kind of tile you have. You can’t use a chemical by itself to polish a tile.

Normally Squeaking floors is caused by the plywood sub-floor not being well attached to its base and when you walk on that portion of the floor it moves, which causes the squeak sound.

The reason you will get mildew on the tile in a shower is because the water is not draining or drying properly. This could be cause of the tile not being installed correctly with the correct slope on the tile floor.

Your engineer was basically saying that you have a high water table, meaning that the underground water is very close to the surface of the ground.

Granite counter tops are normally fabricated to a high polished surface that makes it easier to maintain.