This thread is proof that I’m old and out of touch - so many names I don’t recognize at all! All I can offer is a vague “recast with K-Pop” and that just comes to mind because my granddaughter is obsessed so I’ve seen more of that than any geezer deserves!
Now, if you want to recast with stars from the 30s and 40, well, that’s another thread entirely.
I’m seeing the other Benedict, Benedict Wong, in the role.
And St Vincent as Columbia.
Benedict Wong as Riff Raff?
Jeff Hillier could do quite a creepy Riff Raff, I think. And he’s done musical theatre.
Borrowing some candidates from above, I’d go for Dove Cameron (who can dance) for Columbia and Natasha Lyonne for Magenta (who doesn’t sing much).
Benedict Wong as the Criminologist would be fun, but it’s the sort of role they always get Charles Dance to do.
Rocky - Dwayne Johnson
Dr Scott - Hugh Jackman, just because.
Based on his King of Cats, I can see Lukas Gage as Frank.
Jane Levy as Janet - she’s older but still looks much younger.
I thought we were talking about the criminologist.
Yes, but I was suggesting that he might also make a goof Riff Raff.
I’m thinking Johnny Depp for Riff Raff.
Just no, Depp’s too old, and I always think of Riff Raff as a skinny guy.
Jeff Goldblum as Dr. Scott.
Whoever is cast as Riff Raff has to be able to write a new song or two, just so the remake seems fresh. Perhaps Lin-Manuel Miranda? (the only contemporary stage musical writer I’m familiar with).
I like the Lady Gaga suggestion.
I’ll add Natalia Dyer for Janet, she’s got the wide-eyed look that’s right for the first half.
I thought about Natalie, seems like a solid choice, she looks young enough.
Too old. Rocky needs to be a young beefcake. If we’re gonna cast a wrestler, how about MJF?
Would a muscle-bound young female work for Rocky?
I’d be worried that if Rocky is a female, then you’re remaking Weird Science, not Rocky Horror.
I think gender is so fluid in Rocky Horror, that you could cast anyone in any role and make it work. The important thing to me is to maintain the queer relationships, and not make everyone straight, just with a bit of kink. Though if Frank-N-Furter where also a woman, then the corset and fish nets would have to be replaced with something similarly male coded.
I do think that no matter what the gender of the characters, the song should stay I Can Make You a Man.
Pink?
Any color, really.
Just kidding. 
Yes. I concur.