When you want smooth walls that are easy to finish.
You cannot use sheetrock as flooring, period. If you meant on a wall, there is no reason you cannot put sheetrock over tiles. The question is why would you want to! Why not remove tiles and material behind, which is probably sheetrock, and then install new sheetrock. If it is an area prone to moisture you could use moisture resistant sheetrock. The job would look better and you would not lose the space by adding over existing material.
You can use drywall nails or drywall screws. I prefer the screws.
No, you can use other materials.
Regular mud.
should you install sheetrock horizontal or vertical
Yes, sheetrock is fire resistant.
No it will actually ruin your Sheetrock or Drywall
it just adds lime to the soil. I will help if you need lime.
I would use about a 5 pound bucket. It all depends how far apart your sheets are and how good a mudder you are.
yes
To remove Liquid Nails from Sheetrock, use a putty knife to gently scrape off the residue. You can also try using a heat gun or hairdryer to soften the adhesive before scraping it off. Be cautious not to damage the Sheetrock while removing the Liquid Nails.
You don't need a drill bit for anything on drywall.