1. Type K.
3. I don't know. Since all codes are made into law at the local level you would have to learn the local requirements.
4. Absolutely do not allow the piping to be in contact with the concrete. I would encase the entire line under the slab in foam insulation and use the same as a sleeve when coming through the slab. Even better (if at all possible) is to not have the piping under sthe slab at all or at least not have to come through the slab.
5. Below the frost line. I would have it no less that four inches below the slab.
6. Again, you do not want any piping, including a well casing, in contact with the slab. Use some kind of spacing material around the well casing that will keep the concrete from touching the casing. Even wrapping several layers of corrugated cardboard around the casing (approximately 1/2 inch total thickness) will work and after the slab has cured you can dig out this cardboard and replace it with something water resistant.
Often piping coming through concrete will have a wrapping of heavy thickness plastic tape to prevent contact with the concrete. While this is good (and I would also do it) the best installation will have some kind of sleeve or at least a space between the pipe and the concrete.