Okay, I recently re-watched 'Repo: The Genetic Opera'. Don't judge me, but I think it's one of the best rock/metal musicales. And I thought... Minotaur Hotel rock-musical? It's not a real idea, and I'm not ready to adapt the visual novel to the musical. I just started to learn vocal, and plan to buy a greek bouzuki (expensive stuff, these rare instruments). But imagine, something rock-ish, with Greek motives (a-la the Hades game soundtrack) with vocals... by the way, what's your opinion on how your favorite character could sound like? :)

Maybe just because he plays the title role in the opera The Minotaur, but John Tomlinson feels like a good fit for Asterion's singing voice:

but he does have a real good low voice-- warm and resonant, rich but gentle. Suits Asterion.

P, Argos, and Luke are definitely tenors. Kota, Storm, and Khenbish probably baritones. Themba is another bass. And the cobalts all altos/countertenors. But I can't think of any direct reference-points for them. Haha

(And be sure to get an Aulos too, so it can be like the music that accompanied Aeschylus/Sophocles/Euripides plays (which were themselves musicals or operas))