I'm interested in how your tank goes!
I'm doing exactly the same thing with a 1.5 gallon cube, and thinking of trying to move it to a 2 gallon cookie jar (it looked cool on google images...). No heater, no filter, only a desk lamp. I've currently only got a tiny rhizome of java fern, a pea-sized dwarf lily bulb that's starting to sprout, a huge amount of Christmas moss, and 3 bloody Mary Shrimp. Apparently the desk lamp I've got on it is enough for the moss to pearl every day. The shrimp seem happy, so I'm happy.