I took these for my own show, so not a headshots job as such. This was the full cast of Superheroes Don't Give a Shit! in their costumes (including me as a hedgehog.) The setup was very simple - one flash on camera right into a hastily assembled V-flat made of foam board (the back of old banners gaffer taped into a 7 foot high flat). A bare flash to the rear on camera left pointed at the subject's back on fairly low power (1/32 I think). The background is a wrinkly projection screen with two floods borrowed from the theatre pointed at it from the floor. Both were gelled with the appropriate colour for the character's 'superhero school' - and then hastily turned off because the floods do a really good job of melting through gels. The shot of Alfie has no gels on the floods, so that's just the colour they are relative to the flashes. There is very little editing and no photoshop on these, because they were shot the night before they had to be printed. We used black and white crops from these for the house programme, and the colour versions were hung in the foyer, replacing the theatre's usual show photos in their frames.
There's more information on the show over at my performance site: Superheroes Don't Give a Shit!