You are correct! The tile will sound hollow when the thin set isn't hardened. When the thin set hardens the tile should sound much more solid.
No, you should never do that, it will defeat the purpose of having ceramic tile and it does not look good.
Yes, but you should you use an adhesive that is ductile
You can install the vanity first. Then, install the tile up to the vanity and around the pipe for the toilet. Then, install the toilet. That way, you do not have to replace the tile should you ever have to replace the toilet.
Ceramic or neo-ceramic. It is designed to radiate heat.
I do not think that is a good idea.The rubber flooring should be removed and then new ceramic flooring should be laid on.
You should not adhere tile on top of tile. It is much better to rip it up and install on a secure surface and make sure it is smooth level. If you find yourself in a situation where you can not/should not remove the tile (e.g. if there is asbestos tile underneath or if there is a radiant heat systems under and you don't want to risk breaking/puncturing it), then the alternative is to pour 1/2" (or more) of self leveling cement and then install on top of that.
Yes you should.. the unglazed ceramic is not good for you, I belive it's a long the lines of one of the cancer causing.
It depends on the condition, material and surface of the laminate. A linolium floor, for example, is soft composition with a textured surface. This makes a horrible foundation for ceramic tile, giving room to crack the grout between tiles. A hardwood-type laminate is smoother and harder which is a better foundation. That said, the best thing to do is rip the laminate out and start fresh.
No. They should be good thermal insulators.
There is no reason to wet them.
Granite
1"