I have a couple of "learned from experience
" thoughts for you. If you plan to plant anything in your streams, make sure the flat areas between your falls are deep enough to hold 3-4 inches of water.
If for any reason you have to turn off the pumps, due to a leak or a 3 day power outage (been there). Your plants won't die and it tends to look more natural.
Make your stream and falls at least 6 inches deeper than you think they should be. When that water starts rushing you'd be amazed how it can climb the rocks on the edge.
Your pumps should not be at the lowest pond depth. If for some reason the stream gets diverted you won't empty the whole pond.
Give careful consideration to the surrounding terrain and water run-off; you never want run-off water in your pond.
Just my thoughts.