I wouldn't put anacharis in your tank as is is a rooted plant. Mbuna will dig it up and it will constantly be floating around the tank. Java moss and java fern may work better as they should be tied to a rock or piece of wood. I am not sure if the fish will pick on them or not. Anubias is a plant that I've had good luck with. None of these really require CO2 though and unless you are using very bright lights, the CO2 will not have a noticeable effect on plant growth. Also, be careful with it as it will drop the pH of your water through formation of carbonic acid. To be honest, I've never heard of anyone dosing CO2 in an African tank.
Yellow labs may be ok for a bit (I've had a group in a 29 for a while - don't tell anyone, lol), but you will need to move them up to something bigger than your 26 eventually (40B or 55). Personally, I'd go with dwarf peacocks or better yet, some smaller Tangs for that tank. Smaller Julidochromis or Neolamproogus would be nice. While not as colorful, they are every bit (if not more) entertaining than mbuna in a small setup.
Good luck.