The Beach biome should come in three variants rather than just 1. Also, having 5 variants (warm and frozen) could be a little excessive - only 3 is really needed).
First, the Normal beach would just be the current beach we have in Minecraft with not much else changed. Seagrass and Cod could generate here. Second, the Lukewarm Beach would have the palm trees promised in the Desert biome vote update, and the water color would match that of the Lukewarm ocean. Seagrass, Tropical Fish and Pufferfish could spawn here. Finally, the Cold Beach would have the cold ocean water color, and it would generate as Gravel rather than sand (see beaches in areas like Alaska, the Pacific Northwest, and islands above Antarctica). Salmon and Cod could spawn here, however Turtles wouldn’t. Seagrass generates here.