|A scene from Betty White's Off Their Rockers|
What if they're siblings?
What if they were childhood or college friends?
What if none had planned a religious life when they last knew each other? What were their plans and what series of events drew them to the choices they ended up making?
What if two of them were lovers at one time? Which needn't be a traditional combo. ;-) What if it was a love triangle?
What if they're aliens practicing to be human? What if this is a just-a-bit-off simulation for aliens to practice or play in?
(Feel free to imagine non-Judeo-Christian religious callings.)