Am I imagining things or are the wedding dress sleeves uneven (longer on back/side area?), especially in the US productions? If so, is it a historical detail?
The lace seen on the sleeves of most of Carlotta’s and Christine’s costumes are called engageantes. It began as lace decorations on the shift in the 16th and 17th century, and by the 18th century it had became a separate lace decoration that could be basted or pinned to the dress, under the sleeve flounce:
These were almost always longer in the back and shorter in front. This is for practical reasons - shorter lace in front means it won’t get in your tea or on your letter or whatever practical thing you’re doing. In use it would look something like what’s seen in this portrait:
But this is 18th century fashion, you say? That’s correct. But this and similar styles were revived in the mid/late 19th century, in what’s known as “historicism”. Styles of the past were revived and reused, with gothic marvels, antique temples and rococo furniture. Palais Garnier is a good example, being built in a Neo-Baroque style. The same applied for fashion, where styles from all historical eras were revived or served as inspiration in different ways.
Haute Couture king Charles Frederick Worth was one of the pioneers here in the 1870s and 1880s. Here’s a wedding dress from 1874, showing similar engageantes as the 18th century dress:
And this is the style Maria Bjørnson designed “Phantom of the Opera” in - the historicism style, where there’s lots of historical references and inspirations. Most productions makes the engageantes longer in the back than in front, as it was done historically:
But I’ve also seen examples where the lace is just overhwelming and more or less the same length all round:
(both examples are from Japan, though the wedding dress is an elder one, while the dressing gown is a newer one)