For me, there is 2 ways to go. If you want a planted tank with a few shrimp, then go with plants and whatever else. If you want a shrimp tank, go with moss only and a few floating plants. I usually get a piece of driftwood and tie moss to it with fishing string, as it lets tannins soak out of the water from the wood, gives the baby shrimp lots of hiding places in the wood and the moss gives them and the babies a source for micro-organisms to grow on which they eat. If you want a shrimp breeding tank, keep it simple, no plants means no CO2, no ferts, easy to maintain and easy to see all your shrimp and find them, monitor them, etc. In a hugely planted tank, its hard to see your shrimp, then you don't know if they are dying or hiding until one day you have no shrimp left. Keeping it to a minimum lets you watch the shrimp and babies.
Java moss is fine, most of us use it or xmas moss or some sort. Without ferts and co2, it doesn't grow that fast and when it does, you just rip some off and use it for your next shrimp tank, because once you start with one, you can't stop. lol.