10-12 neon's would be nice. The loaches will get big 12- 16 inches or so each, though an you might have a problem in a year or 2 after they achieve full size. Just to let you know.
Clown loaches get huge, really huge. I reccommend moving them to a bigger tank in a year or 2. I would go as high as 15 neons, if the clowns move elsewhere, 20-25 neons.
I've never had barbs, but aren't most of them schoolers? if so you might want to get several more, they will be happier and more active in a bigger group!
The redline is a fish which can grow to 6". Because there is not a lot of information on this fish due to its newness to the hobby I would be wary about putting a small fish like a neon with them.