To me Blue Lagoon is Windex. Of the others, I like Tahoe Blue the best because it looks most like my pool frankly. Keep in mind that your pool only goes to 7'. When you look at pool pics with those finishes, they could be deeper which will be darker. I think you would want to err on the side of darker water (so darker finish) because a) you are most likely to be by the pool when it's sunny - which makes the water look lighter, versus when it's cloudy, b) 1/2 of your pool is shallow, c) plaster fades over time, the pebbles don't but the plaster binder most certainly does (see some recent threads where they show removed samples and the exposed side is way lighter than the underside). Reason C is the biggest reason to go on the darker side. It will fade.
You also have big tanning ledge where the water will be quite light in color. The reason I choose Tahoe over Tropical is because the finish itself (not water color) of Tropical is more blue, which I'm not as big a fan of for the shallows where you really see the plaster color more than the water color. I like the greyish appearance of Tahoe.