the ADFs will do a fine job at cleaning the bottom of the tank for you, and you dont want anything to compete for food with them because they arent the most aggressive eaters.
as i said before, your best bet is to get some more neons.
Cheers, Ive just read that sucking loaches can be a nightmare anyhow. The LFS sold one to my friend the other day and said it will stay about 2" in length