Anybias Nana is a great low light plant that would do well if you can have a small piece of driftwood in there for it to attach to and yes do add a couple of shrimp in there too. They have little heaters you can get for a 1 gal and a mini hob filter would be perfect. I have freshwater shrimp in my 30 gal and they are funny characters, they keep the plants spottless of algae and are very good cleaners.
You would have to supplement them with a few flakes or algae pellets in a tank that small though.
