Hertha's POV is very enjoyable to read, especially for the subtle satirical tint in her opinions on the goings-on in the opera house. That's probably indeed how a XIX century aristocrat would react to the music styles and visuals of the musical, especially the movie version. I'd say for a reader "in the know" it's quite apparent from the start that the narrator is not Christine - her voice is noticeably different from how you usually write Christine, she's more pragmatic and comfortable with the high society. However, I'm not sure that I wouldn't be fooled if I wasn't familiar with your writing before and with your "behind the scenes" plans.

I love the characterization of Raoul there, he's so exuberant and genuine. His relationship with Hertha is clearly full of respect and affection, even though he doesn't love her.

I also love how elegantly you explained the presence of the white modern-ish dress in the ancient Carthage. :D