Tile – How to you paint tile

If your tile is not secure, then the backer is not secure either. You will need to gut it to the studs and install water proof membrane, concrete board or heavy hardy-backer to tile over. The window frame must also be carefully water-proofed as well and trimmed out with a moisture resistant material. Get some professional advise on this one, a new tile job is not cheap or easy and be a shame to have a leaky, grout dropping job when you're done.

As far as the type of tile, ceramic or porcelain are similar products, difference being the hardness grade and the type of glazing. Porcelain is always a better choice in my view as the surface glaze is smoother, easier to keep clean and usually a harder grade.(3 to 7) prices can vary wildly, usually again because of the glazing and hardness factors. Designer patterns also effect the cost as well.

In the to-do section of the care instructions you posted, it suggests "Use an all-purpose, non-oil based household or commercial cleaner." OR, it says, you can use vinegar/water.

I think you are over-analyzing. The normal floor mopping solutions like Pine-Sol or a Swiffer will work fine. Just don't use anything abrasive that will scratch the tile or an aggressive bathroom "tile/grout cleaner" that is meant to bleach and renew grout that is stained.

If you're concerned about a particular cleaner, you could always test a small section that is out of sight. You can also apply a "grout sealer" solution over the grout lines. This is tedious, but can help slow down staining of the grout.