They stay small, and like to eat algae, but they don't exactly spend a lot of time on the bottom. They also need to eat quite a lot - cucumber, algae tablets, etc.
The embers will colour up quite a bit with good food...but they are only the one colour. As for other colourful small fish, maybe you might like a couple of fancy guppies instead. Or a couple of killies (they have amazing colours and there are a number of people on here who could 'hook you up.') If you really like neons, maybe you should go for them. I like them too but they can be very shy if they don't have any dither fish to give them confidence. I find danios very good and confident, very fun to watch as opposed to neons who often hide or just sit there in the water when you are looking at them! Celestial pearl danios would be great, but they cost a bit. :roll:
You could always just go with some dwarf loaches. They are great to watch so even if your tank only had a group of them and an oto it would be quite interesting. Look up dwarf chain loach. They need to be in a group of at least 5, but they would look great.