Love your design. I've seen it where the columns have been tiled in 1" tiles and the wall has been stacked stone and it looked great so I think what you're planning would also look fantastic.
Here's one.

Here's another.

Those look great. Here is the other design we really like as well. Both are similar in style and allow us to be creative on the feature wall.

The element I like best about the first design is that the spa is in the deep end. What happens is that you will find the kids want to jump off the spa edge into the pool. Better to do that in the deep end.
Take it from my experience, you won't be disappointed in making that decision.

I agree with the spa location, but my hubby doesn't like it that close to the house. I also think we will have kids tempted to do that from the feature wall across so will have to establish rules on jumping area. Still working the designs a bit. This is so difficult to get everything we want in look, function, and expense! The proposed pools are both presently 33x24 and are 3.5-8.5" deep, with tanning ledge.

I agree with the difficulty in all the decisions. We had the similar issues. Still debating whether to increase our deep end to 8' from 7'...!