I find it really interesting when actors have a different voice than other actors in the same role, so they lower/raise the keys to fit them better, they option down/up for riffs or just simply sound very different to other actors who played the same role. What are some good examples of this?
Off the top of my head, I can think of:
Taye Diggs as Fiyero/Hedwig
Kendra Kassebaum as Glinda
Julia Murney & Shona White as Elphaba
Sara Bareilles & Jordin Sparks as Jenna in Waitress
Hello Dolly is a great example, because I think the songs' keys were adjusted for each Dolly (or most I've heard).
I must say I haven't heard Paulo Szot in South Pacific, but I will definitely check it out — I'm guessing he sounds quite different since he's a baritone playing a (typically) bass role.
Jennifer Simard has a deeper, more monotonous tone when it comes to both singing and acting in the Adult Women tracks (Mean Girls), compared to Kerry Butler and Catherine Brunell. I remember her Mrs. George specifically being airier / more whisper-y than anyone else who's played it (which is only two people, but still)