1. For a shrimp tank, I would usually recommend sponge filters, but yours will be larger than the average shrimp tank. Multiple sponge filters might work, but you might also consider a small to medium canister, eg. an eheim 2215. If you use a canister, you will want to cover the intake with a sponge to prevent sucking up baby shrimp.
The only problem with sponge filters in a planted tank is if you run them off an air pump the surface agitation releases any co2 in the water (I agree they are good filters in shrimp tanks though). I would use a canister but seriously the bioload of a shrimp only tank is so low you could get away with a tiny one. If you want to add fish, like you mentioned you might, you should go bigger. Blocking the intake of the filter is a good idea.
2. A double T5HO fixture will be sufficient for most plants you might want to grow.
Just realize in a tall tank the light has a bit further to travel.
3. Red cherry shrimp are a better choice. Ghost shrimp are difficult to impossible to breed, and not very interesting looking. Cherries breed like rabbits and they are a good balance of being easy to care for, yet still nice looking. They are probably the easiest ones to find as well. A perfect choice for a first time shrimp keeper.
Ghost shrimp are actually pretty evil little shrimp... they aren't compatible with any other shrimp, as they will eat them. I would recommend an algae eating shrimp, cherry shrimp are great. You could also do any of the crystal varities or amano shrimp.
4. Newly hatched shrimp are a prey item for pretty much any fish that can fit them in their mouths. The only fish that will leave them alone that I know of are otocinclus catfish. If your tank has dense enough plant growth for them to hide in, enough babies might survive to sustain a colony, or maybe not.
You could probably add some very small schooling tetras or rasboras. Otos are shrimp safe.
5. Sponge filters: $7/each. OR Canister: $80-$100. Light fixture: $100-$150. Shrimp: $1-$2/each.
6. Since you're set on having fish, you might want to consider just omitting the shrimp and focusing on plants in this tank, and maybe having a smaller tank devoted to the shrimp. Then, once your plants fill in, you can add some of the shrimp to the plant tank and see how they do. If you stick to small schooling fish, they might not eat too many of the shrimp. But anything bigger will probably pick off most of your baby shrimp.
Below is my 10g shrimp tank. Lighting is 2x 7w CFLs (40w equivalent), sponge filter, 50w heater, red cherry shrimp. Plants: java fern, water sprite, moneywort, ludwigia, a few strands of dwarf hairgrass, and a marimo ball. Substrate is just plain pool filter sand, and I don't use any supplements or ferts. The only plant that needs much pruning is the watersprite, the others don't really explode with growth, they just kinda survive, which is fine with me.
