Java or Xmas moss.. java fern are low tech anubias. You could put a prefilter sponge on your hob. Shrimp don't really care about substrate. Just don't overfeed.buy 10 or so cherries a nd a month later you'll have a bunch..
Low tech? Just do some anubias and moss. Shrimps go nuts for moss, and in reality thats all you really need. I use an aquaclear on my 20long shrimp, I also use a sponge filter too... they love picking at the sponge. your light should be sufficient for low tech, especially if its just mosses.
You can use a nylon stocking as well for the filter intake. That's what I use (black one), and the shrimp hang out on there all the time eating away. And moss is a MUST for shrimp tanks. Cholla wood is awesome too.