Yah...I am going with real plants for this first time with my itty bitty tank, if for no other reason so that I can put an extra fish or two in it. It looks like your tankmates are pretty peace loving. How about some cherry shrimp? They would add nice contrast to your white substrate, though I am not sure if this would stress out the shrimp. A small black pleco? Kuli loaches are supposed to be fun to look at but the ones that I have had were nocturnal, so not so much fun...not sure if you have any particular theme or objective.
Like the above said, I'd try out a few plants (Anubias Nana is a favorite of mine for small tanks, Java Fern as well). You can get away with like 2-3 tiny fish when you do that.
Stock wise... well, a Betta would limit your fish down to 1 fish, but in a tank that size 1 is all that really fits. I would suggest a sparkling gouramis, they are very pretty (if shy) fish that do well in small tanks. I'd also suggest cherry shrimp as well, since, like red devil said, they would add a spark of color into the tank.
you won't need a ton of light , can add live plants(subwassertang, jave moss, java fern etc)
believe it or not the shrimp are quite active and it makes for a nice tank in my bedroom.
You should go with some moss too! Shrimp really like mosses And there are all kinds of places that ship and there are a ton of members on here that would probably be more than happy to send you some