JBroadway said: "I don't love the accents on the CR, but I'm not surprised that it happened, considering everyone was b*tching about how the Broadway production "didn't feel French enough" - one of the sillier criticisms of the show IMO."
I agree, the show already feels far more French in the new version, regardless of the accents. Beyond the updated orchestrations, with the string and accordion-heavy instrumentation that's usually associated with the French aesthetic, the story is more playful and emotional, hallmarks of the storytelling seen in French art, especially in the original film.
Just with regard to Audrey Brisson's accent, I've heard her perform in other accent/s via streamed productions of other shows, so I'm not actually sure what her default English-speaking accent is. I assume that a French-Canadian would be able to emulate French-accented English better than most, but I don't know for sure.
What would be odd though, if indeed the British cast transfers, is the variety of accents if they do not use a French one. The UBER sexy Chris Jared who plays Nino has a very thick Scottish brogue. Audrey, as stated, has a French Canadian accent, and the rest of the cast have accents from all over the UK.
My biggest issue with the Broadway production was the artwork and the use of Phillipa Soo's decapitated head to advertise the show. I still think that was a significant factor in the show's lack of success. The UK artwork is a major improvement but still no one has really figured out how to market this show.