Discus, angels and ornate should be fine together. I know someone with 3x 14" ornates and some other 12-15" bichirs with some discus and some altum angels in his tank. They are doing fine and nothing bad have ever happened to the discus and angels.
Best thing to do is to separate the ornate for a month with some other bichirs. See what's the aggression level of the ornate, as every ornates and the rest of bichirs species have different aggresion level. If you finds out that your ornate is very aggressive the get another ornate. If it's not aggressive as most bichirs are, then misx them together. Make sure the discus and angels already settled in the tank before introducing the ornate.