serge and jane (default)
Honestly, the German stage version (which is what I assume they'd be working off of) isn't that much darker than the Disney movie. Main differences are that it is made more obvious that the gargoyles are figment's of Quasimodo's imagination and Esmeralda stays dead at the end.

Both changes work for the better IMO, they make the Disney version more thematically consistent
without quite making it as grim!dark as the novel.