For your the top-view example that’s your third image, the water appears to be underneath the water as if the sand is reaching across disturbed shallow water. An edge of a lighter color can represent a spray line to swap and a darker color can represent wet sand to make the water look higher than the land.
Maybe not relevant to top view tiling (I haven’t taken a close look at that) but here’s a side view experiment you’ve inspired.
The bottom layer has lower saturation than the previous two stripes, is darker than the top to represent the loss of light reaching lower depths, but is also hue shifted slightly from green and blue.
That shift is to reduce contrast with orange and pink/red sprites. In reality, humans can see fewer colors the deeper the water, and reds are quickly lost.
(*edited again because early posting doesn’t result in the highest quality *😅)