Starting to think foam on beaches is just the very thin roll of the water. Which may be more appropriately handled by displacing the water along shore, so water rolls up it a bit and thins out.
Another thing that bothers me, is when you mask out the waves/foam setup to have areas with no waves and vary it up. If the scalar is slightly gray, you'll loose all foam, but still have wave displacement, and it just looks weird. It doesn't seem like the surface masking isn't accurate between displacement and colour. I've noticed this before with other stuff. Use a surface layer and offset it add colour, add a min alt, and than notice how colour transitions to zero far before the displacement does. This causes issues all around TG. Like fake stone colouring, or custom fake stone colour, etc.
