A lot of ppl keep Discus with Tetras- Cardinals and Rummy nose mostly, with no problems. I'm surprised baby Discus would attack your Neons-and that the neons would let them do it. Neons are a bit small to be kept with Discus.
Its better to add the Discus to the tank already containing (fully grown) tetras, this will give the tetras a much better chance. Do it the other way round and the Discus may just think-thats nice looking food.
I think I recall reading an article by Jack Watley that cardinal tetras make some of the best tankmates for a community discus tank (though he believes discus should not be part of a community tank). Didnt mention neons.
Drew