Very cool. Let us know how the building process goes.
Here is my suggestion for you for a 'sustainable' population of shrimp, fish and snails.
Start with your base: Plants. You definitely need plants if you want to keep shrimp.
I'd do a lot of moss, driftwood, anubias, column plants, maybe some filling ones like wisteria and such. You can do a little more research for that on your own lol.
Then a sustainable population of shrimp? If you're just starting out, I'd honestly start with neocardinia species. If the tank will be heavily filtered? I'd rule out orange shrimp. The prettiest and easiest shrimp, which will keep a population, is some variety of Red Cherry Shrimp. You'll be very happy with how interesting they are, especially if you keep some kind of drift wood.
More inverts? Another sustainable population would be, my favorite, Dwarf Cajun Crayfish. Very peaceful and modest breeder which will feed on detritus and stuff like that at the bottom.
MORE inverts? You'll obviously get pond snails, but I'd recommend 4 horned/zebra nerite snails. Although they wont reproduce, you'll be set for a few years with them. I'd also add Ramshorn snails. They're SO HELPFUL. They keep my tank so clean and they don't reproduce QUITE like pond snails.
Fish... This is difficult because you want to keep inverts and most fish will just eat them right up. SO it limits your fish a little, but in all reality, opens your choices up even more.
I'd say do two varieties of micro rasboras in large schools. Maybe 30 overall rasboras, of two different species. Chili and Exclamation point would be awesome looking.
Lastly, I'd say get about 6-12 peppered corys. Or even more Corydoras Hasboreas/Pygmaeus instead.
That'd make a pretty banging tank, in my opinion. And other than feeding every few days, if you're heavily planted, it will be pretty sustainable. And you'll probably never have to purchase fish for the tank again. Each species, minus the corys and nerites, will breed.
.
