Kim's right. The wall, and the spa, too, are going to create blind spots where you won't be able to watch swimmers in the water, including kids under the dive rock, while sitting in certain spots on the far side.
Regarding the pergola size, are you going to have a table under there? Tables can be huge in terms of the space they need. And sometimes that's not obvious until it's too late. It's the size of the table, and all the chairs, but chairs pulled out a foot or more from the table, and then 3' of clearance beyond that (to allow folks to get in and out of chairs, lean or scooch chairs away from the table, and still allow traffic coming and going behind and around all that! It ends up a pretty large dimension, even for a smallish table.
Do you already have the table? Or one of similar size? Pull the chairs out and add 3' all around that and measure. You'll see what I mean. And if you're going to add sun shades over or along the sides of the pergola, that's something else that makes them feel smaller.
Personally, I don't have any use for a "roof" that consists of 2x2s spaced 6" apart (if that's what you've got there). Doesn't provide any relief from the sun, or protection from rain. First thing I did to mine when I bought the house was to put a proper roof on each. That's where we hide from the sun. And I like to go out and sit under them when it's raining, too. (Protects my furniture, too.) I added sun shades on the west side. Around 3 or 4 o'clock the roof doesn't block the sun enough, and after that the sun would be quite annoying without the shades. My landscaping provides some of the sun blocking, so that is something to consider about your landscaping and plant selection.
The rendering doesn't indicate what is bordering the pergola. So depending on what that's going to be, you might want to have the landscaping extend more towards the pergola, at least along that one side, to create a nice backdrop and possibly a sun block.
Just keep in mind: any stone work that penetrates the water (this goes for stone on wall and spa, too), can turn into a cleaning problem. Read here about effervescence. It leaches out of, and collects on, stone that is subjected to water and evaporation and is not fun to clean. That's why there is edge tile: a nice smooth, easy-to-clean material. Stone descending into water is a very nice look, just be aware of what you're getting into if your pool has a lot of that.
