Ok. Here's the thing. Self-sustaining tanks are only self-sustaining if they have a MASSIVE water volume, much larger than what you have now. Why? Because in order for it to self sustain, you have to have enough nutrients to fuel the phytoplankton and primary producers (algae, microalgae) growth. Then, you need to have enough of those to fuel micro-plankton like daphnia and copepods. Only after that is done, can you add the secondary predators like fish or micropredators (think small nano fish like chili rasboras, etc.), and if they breed, you need a few predators to take care of those. Again, larger than what you have now.
That being said, if you only plan to have shrimp, then your current plan is a good one. Make sure that you look into freshwater DSB's, your tank has the height for it, it seems synergistic with the Walstadt method but may need modification, and coincides with your plan to add planarians and other snails:
Deep Sand Beds
Unfortunately, you WILL need to do maintenance on the tank. At some point, you'll need to get rid of non-measured organic wastes, and add in vital minerals, best done through a water change. You'll also need to feed your organisms (I prefer gel vacation blocks for my shrimp, of which you might want to consider leaves (think oak, beech, indian almond, etc.) which you can read about here:
All the leaves are brown? ? Seriously Fish
Not many creatures eat hair algae nor blue-green algae/cyanobacteria, and if you get that, then have fun

. Nerite snails are good at removing "hard" algaes like green spot, and shrimp (Neocaridina and Caridina species) will also eat softer algaes (diatoms, green film algae, etc.). Daphnia will take care of most bacterial blooms and micro algae (green water) blooms too. Copepods can get in hard to reach places and eat most algaes too. Just know that you will eventually have to do some sort of cleaning in order to keep your tank aesthetically pleasing.
Oh, a few things for the future: for fish, that type of tank (portrait style, etc.) is not good. You really want a tank with a larger surface area (i.e. the configuration where length x width is the greatest). It also helps light penetrate through for plants (less depth for light to escape from the sides of the tank. Don't bother with some of the older versions of denitrification filters: they essentially move water really, really slowly through a canister, to the point where water just gets deoxygenated, forcing bacteria to use NO3-, and release N2 gas (which, you shouldn't need due to having plants that'll take care of the nitrates anyways...).
Aside from organisms, what plants were you considering adding into your tank? Note that carpet plants might not do too well in your tank, but more stem-y plants will like it.