Within "blockstates/gray_terracotta.json" it references variant 0 where it should be referencing variant 16.
Within "blockstates/stone_slab.json" and "stone_stairs.json" it references variant 0. There is 0 variants in models that in turn references a non-existent stone variant 0 in "textures". I believe these variants intended to be 16 to follow the variant naming convention of 1-16 that most of the rest of the resourcepack follows.
Description of bug
Within "blockstates/gray_terracotta.json" it references variant 0 where it should be referencing variant 16.
Within "blockstates/stone_slab.json" and "stone_stairs.json" it references variant 0. There is 0 variants in models that in turn references a non-existent stone variant 0 in "textures". I believe these variants intended to be 16 to follow the variant naming convention of 1-16 that most of the rest of the resourcepack follows.