It is the Sandstone liner, no tile. We use Vynall as our manufacturer but it is offered by many different companies as well. It is a brownish/tan finish that gives that beautiful turquoise in the sunlight.

That is exactly what we were going for and I think we achieved it. Your plan looks great. One change I would make is to make the spa a spillover. With the proper control system it makes the spa maintenance free because it will kick the spill on every day and replace spa water with pool water. Hit another button and it stops spilling and becomes a stand alone spa that you can heat to your desired temp. And the stone work for the spa and water fall match the liner perfectly.