Second is coffee a GRAS and what is GRAS?

GRAS is an adjective, not a noun. So the question should be "Is coffee GRAS," rather than "Is coffee a GRAS."

GRAS means "generally recognized as safe." It is a term derived from the Food, Drug, and Cosmetic Act, administered by FDA. If a food ingredient is GRAS, it is excluded from the statutory definition of a "food additive." This is important because a substance that is excluded from the definition of a food additive does not need FDA premarket approval. Food additives, by contrast, must be approved by FDA before they can legally be used in food that will be sold in interstate commerce.

FDA has a regulation that says that coffee extracts are GRAS but there is no regulation expressly dealing with coffee as a beverage. Nevertheless, coffee is probably GRAS and FDA has apparently never opined to the contrary.