Okay, well finally got some more done today.
Began foaming the background. I learned the hard way once before that putting the foam directly on glass, or on glass coated with silicone, is not enough (65 gallon DIY aquarium background, pulled right off the wall when I was cycling the tank)! It can and will pull away from the glass eventually. However, if you silicone a piece of plastic egg crate to the back of the tank, and foam onto that, it will hold its shape and not pull away. If you put the straw from the great stuff into every cell of the egg crate, you can inject the foam behind the egg crate, and then move to the next cell to foam on top of it. This way the foam completely encases the egg crate and will hold on very well when it cures. It's more time consuming doing one cell at a time, but in the end you'll have a background that will hold its shape and stay in place!
I tried keeping the foam as thin as possible, I didnt want a thick background as I dont want to take away from the overall cage space. So, I didnt embed any planters into the foam, instead I'll use a few thin pieces of cork bark placed in the foam and I will be able to glue tilandsias and other epiphytic plants to them.
I made the waterfall shelf out of a piece of corkbark that I rounded and hacked up with a sharp knife, lol. I tested it out with a slow flow of water from the sink and it had a nice cascade effect, similar to the one in the photo I liked.
Tomorrow I will turn the tank upright, and finish the foaming. I still have to do the divider, and on top of the waterfall. I may be able to start siliconing the background and applying the coco fiber as well, since it's such a thin layer and the crate holds it in place, it may be firm enough to do that.