It looks really beautiful, but as a Pigg, I really have to warn you about the on-going water cost to this design in terms of your water bill.
Definitely make sure you use as little grass as possible, make sure all the plants are natives so they are climate-appropriate in terms of water use, and make sure your surfaces are previous, so when it does rain, water gets soaked into the ground, and doesn’t run into your pool.
If you’re set on your designer, that’s cool, but make sure he uses natives. If you google “nifty-fifty plants” you can get a list of beautiful native flowering trees, shrubs etc.
And, think of the money you’ll save on your water bill. Water rates are only going up in the coming years. It is estimated that 1/2 of water bills are due to landscapes, so I really encourage you to figure out if you can cut back.