Congrats on the tank purchase. Generally, low light plants do not require ferts so that should make things easier.
Consider anubias, crypts and exotic mosses for your tank. Small plant carpeting will be difficult without moving into more light demanding plants while larger carpeting plants wont really offer the same aesthetics given the small tank. Mosses growning on SS mesh may fit the bill to help carpet the foreground. I have several pads of fissidens that look really great.