Another hack called Pokémon PureRGB says that they found unused ice-looking tiles in the cave tileset, and used them for the Seafoam Island caves.
To me, this makes more sense to use instead of the brown rocky tiles that the other caves use since this cave is populated by ice-types, and later remakes make the cave frozen. If it's not too much trouble or beyond the goals of this hack, maybe you could try these changes to the Seafoam Island cave on a future version.
Another hack called Pokémon PureRGB says that they found unused ice-looking tiles in the cave tileset, and used them for the Seafoam Island caves.
To me, this makes more sense to use instead of the brown rocky tiles that the other caves use since this cave is populated by ice-types, and later remakes make the cave frozen. If it's not too much trouble or beyond the goals of this hack, maybe you could try these changes to the Seafoam Island cave on a future version.