In terms of body types, I wonder if the alternate JVJs are taller than Ramin -- he always struck me as too short for the Phantom, whom I picture as tall and lithe (and older) and for JVJ, whom I picture as tall and brawny.
Regarding Samantha Hill, I saw her on Broadway in, I think, her second performance as the alternate Christine Daae. She blew me away, and I wasn't surprised when she became the main Christine and Marni Raab became the alternate.
BTW, is "alternate" the correct term for an actor who plays some in some of the performances every week? Does it matter if they switch off equally or if one is clearly primary?
You alone can make my song take flight.