Cherry barbs are really nice (I'd like them in a tank one day). The Asian Rummynose unfortunately needs a larger tank than a 10 gal. Despite their small size, the males are rather feisty, and they are active fish. Although you could keep the endlers in the 10 and upgrade to a 29 gal for the Asian rummynose.
Peat Moss and driftwood will only lower pH if the KH (buffering capacity of the water) is already low. Nothing actually lowers hardness aside from diluting with pure water (like distilled water or reverse osmosis water). Driftwood will lower it just a hair, but you really need a large piece to see a significant change.
Before you go around messing with water chemistry, you might want to read this article. It's written by a friend of mine with many many years of experience.