Every input should be its own line on the input list.
Standard input order is rhythm, melody, harmony, Vox. That’s not to say you should split your violins up between melody and harmony, but your Cello’s are typically more melody focused than your violins are. (Thanks Pacabell). Everything builds on what comes before it, so whatever your foundation is comes first, which is usually rhythm. Next comes the feel, or melody, then comes all the sparkle and flavor in the mix or the harmonies. If the foundation is messed up, it doesn’t matter how nice the sparkle is it will fall apart.
Hope that helps.