Looking good, just seeing this thread for the first time. Two things - the tanning ledge, I had wanted about 8 to 9" of water on the ledge, builder messed up and I have 5 to 6" - I would really really prefer 9". The step down might be a bit - 12 to 14" at that level, but I think worth it. You can't really lay in 3 to 6" of water and enjoy it. If your primary concern is the bubblers, I think you'd still be OK on those as well, you've got a dedicated pump to the water features and a valve on each one of them, I bet you can still make them spray any height you'd like.
On the depth of the seat in the hot tub, Sit and measure, I want the water to be up to my shoulders in a hot tub - so do a measurement. On mine from the seat to the top of the water is 18" - ideally I need another 4 to 5" - I'd target 22" at a minimum or maybe do the split seat and have some around 20" for shorter folk.