I am in need of someone who reads French more fluently than myself. Mr. Berjaud graciously gave me a document from his research in the archives of Strasbourg. I will only share a few pages, and I am not sure I am allowed to share the full document without his permission. I will ask him in the next few days, and hopefully, more pages can be shown. I know sometimes historians can be unwilling to share information, but my goal is to help others, and hopefully, someone will help me!
Below is the Revue of the 3e Ligne in Strasbourg on 31 October 1807, found in the papers of Général Baron Alexis-Balthazar-Henri Antoine de Schauenburg titled Revues particulières d'inspection. As you can see below, he does mention the unique uniform of the tambours and musicians wearing celestial blue with red facing.
If anyone can translate the second page, I would be in your debt. The General's handwriting is better than most, but I cannot read every letter, which slows my google translating down a lot.