Of course there's also the over-used and exhaustingly cliched joke of adding "the musical" or worse "the musical!" to any title or name or subject matter *seemingly* incongruous or unsuited for musical to make it hilarious. I've always detested the joke assumption and common understanding that musicals can't take on anything serious or real or complicated.
I'm not saying Lizzie The Musical means to do that, just adding to your comment about the title.
But I actually read the review, and while Lizzie the Musical isn't a great title, Forty Whacks would seem to send the message that it's a comedy or a campy musical look at Lizzie Borden, and this musical doesn't seem to be like that at all, so it would be a pretty bad fit as a title.