In this project you appear to have all voices routed to the same channel - ‘05 - Spitfire Brass B’, ch2. So most of the problems you describe come from the fact that they’re using the same channel.
We know that the naming of voices can be confusing. There’s some complexity here because there are multiple voices, divisi and multiple flows to consider, and we don’t currently have any good mechanisms for organising or labelling these at a higher level. So it can be hard to relate the voice you see in the project to the voice in playback. This is something we hope to improve in the future.