Almost all of them are made on birch and pine tree wood panel. None on canvas.
It depends on the painting, but some even have 4 layers
Yes, it is possible. So please be gentle and clean with micro fibre cloth.
Even trays and coasters are made from special crystal resin for coasters and it is more scratch resistant than for paintings I use, it is still possible to scratch
Yes they are, but till 80 degrees. If it is more, it can leave a mark, for example ring from a tea cup.
I am using very high quality epoxy resin from Europe which is nonylphenol-free and conform to ASTM-D4236 but I suggest to use some small dish under the food.
No, please use warm soap water and fiber cloth to clean products.