Each piece uses a different style. Ellington's upbeat brass and Britten's tone color is set by using various instruments playing the same theme. Tone color stands out as each piece uses different instruments so the listener can get a feel for the music.
Tone color makes each piece distinct from one another because the mood is different with each work.
Melody seems to be the part of each piece that is the foundation for conveying the mood. By using the melody to showcase certain instruments,instruments that set the tone,each piece becomes distinctive.