Porcelain is more durable, better for high traffic areas, it is less porous, has a wider range of colors and unique appearances.

Polished, glossy, satin, matte and natural.

Yes, but it largely depends on the process in which the tile is laid. To optimize the durability of the tile a suitable adhesive must be used. It is advised to follow manufactures recommendations. The substrate must be flat, stable, free of irregularities and clean of dirt and debris.

Mechanically finished on all sides to fit tighter together. A rectified tile is used if thin grout joints are desired to create a seamless look. Generally more expensive do to the cost of cutting, sizing and the degree of difficulty to install.

You need to area (length x width) of the space to be tiled. For straight laid tile always figure in 8-10% over due to breakage and cuts. If the design is diagonal or organic in shape it is important to order up to 15% over.

Most floor tiles can be used on walls, often it is seen as to bulky. Consult the installer or product manufactures for application recommendations.

I do not recommend doing this. The installer has no way to determine the condition of the substrate. Overlapping floors will create a height issue for cabinetry, appliances and doors that swing into that room. The room will have a bulky toe catch. There is an initial cost saving but you will pay the price later.

Every tile has a manufacturers index of slip resistance, the higher the number the more slip resistance.  0.4 or greater is good for showers and outdoors.

Straight cuts – a special tool scores the surface of the tile to brake a straight line. Cut outs – a grinder or a wet saw both with a diamond cutting wheel are used to cut a hole.  A mason bit or a simple glass bit will cut about any tile, taking skill and a little luck to avoid cracking the tiles.

I love this question! I do not recommend painting tile. The final result will not give a high-quality look. All manufactures recommend an epoxy paint, that sticks and gets on everything! Don’t paint tile porcelain or ceramic, replace it to change the color.