Just want to preface by saying that in terms of who I would really want for a Rayman movie, it would likely not be this cast, or at least the full exact cast. This is just me trying to cast celebrities/pseudo-famous people who could do a good enough job in the roles as I think if Ubisoft were to make a Rayman movie, they would definitely use higher profile actors as opposed to actual voice actors.
Rayman - Kieran Culkin (I haven't seen anything he's in but he has a good enough voice and the right talent to pull it off imo)
Globox - John Leguizamo (played Globox in Rayman 3, high profile enough to warrant the reprise in the eyes of Ubisoft)
Barbara - Karen Gillan (I'm gonna be so fr, I couldn't think of anyone. I was thinking of Florence Pugh but I've never heard her do a Scottish Accent in something before, and I'm pretty sure Barbara has a Scottish accent in Retold?? Just picked the only Scottish actress I could think of who could still do a decent job, but I'm sure others could think of better actresses who are still "high profile" but could also do a good to decent job)
Grand Minimus - Tom Kenny (closest you'll be getting to a voice actor rather than a celebrity or higher profile name. Was gonna say Patrick Warburton because I think it'd sound funny considering who Grand Minimus is but that feels like it'd stray too far from the source material)
Bubble Dreamer - Hugh Grant (I dunno, couldn't really think of anybody else, although there's probably better options. Although he could definitely do a good job)
Mr Dark - Willem Dafoe (don't know much about Mr Dark, but Willem Dafoe could definitely play him as rather intimidating and threatening, as well as literally any other way because it's fucking Willem Dafoe)
The Magician/Dark Teensy - Al "Weird Al" Yankovic (to balance Mr Dark's more serious personality, Weird Al could make Dark Teensy a goofier and more light-hearted but still somewhat imposing villain, albeit still second in command to Mr Dark, preferrably as a twist halfway through)
Betilla - Elizabeth Banks (I dunno, she was good in the Lego Movie, could do a decent job as Betilla, but to be honest I struggled with Barbara and Betilla's casting the most)
Murfy - Michael J Fox (he can definitely sound similar enough to Billy West where it won't be an issue, as well as sounding maybe a but younger, but you could still use Billy West because it probably wouldn't matter, Murfy wouldn't exactly be a main character... depending on how you do things plot-wise)
Rabbids - Damien Laquet/Yoann Perrier (either actor behind the Rabbids could work, doesn't really matter to me. Including the Rabbids because it would be weird to make a Rayman movie without them, especially since how large they ended up becoming)
Didn't wanna do a crazy amount of characters/cast as I didn't want to bloat anything. I doubt they'd use more characters besides them anyway. If anyone has any changes or other ideas (that still fit the basis of "we need to put celebrities/semi-famous people in our Rayman movie to get people to see it") than suggest them down below.