I’ve just added Seven of Seven to my buy list (though it will have to wait awhile):
I used to play Joplin half a lifetime ago when my fingers were in shape. Using his music in the soundtrack could backfire, of course. I hated The Sting partly because I disliked Hamlisch’s arrangements. I hope Yoshihisa Hirano uses the original piano scores.
Incidentally, while most of Scott Joplin is lively and cheerful, he did write a few slow pieces, e.g., “Solace,” and some of his later rags, while not depressing, do leave a bitter aftertaste, e.g., “Scott Joplin’s New Rag.”