Very creative! Nice Job!
I would definitely get couple of surge protector strips and isolate different pumps to its own strip thus when one strip automatically breaks for whatever reason, you still have another pump circulating water.
How about small water fall with small water mill utilizing the corner of the wall?
Since you are so good with building, how about diy planters on the deck toward the back?
I even built enclosure to house frogs and newts, etc. Not at home but as window display.