In a ballet of Jack and The Beanstalk
which I was involved in, it was as follows:
Character - Played By
Jack - Taylor
Mother - Jaime
Cow - Lilani
Gypsy - Megan
Vendor - Deedee
Imp 1 - Lilani
Imp 2 - Sarah
Duck - Alayna
Flute - Lea
Giant - Jennifer
The understudies were organized so poorly that upon sickness (or death) of somebody, everything moves around due to one person not being able to be two characters on stage at once.
Who Dies: What Happens
Taylor: Lee becomes Jack, Megan becomes Flute.
Jaime: Lauren (Narrator. Somebody else will the narrate.) becomes Mother.
Lilani: Deedee becomes an Imp and nobody(!) is Cow*.
Megan: Sarah becomes Gypsy.
Deedee: Jennifer becomes Vendor.
Sarah: Deedee becomes an Imp.
Alayna: Lilani becomes Duck, Deedee becomes an Imp.
Lea: Megan becomes Flute.
Jennifer: Taylor becomes Giant, Lea becomes Jack, Megan becomes Flute.
Why couldn't Megan just replace Jennifer? Don't ask me. It's not a complicated part. Maybe she was too small, but I think she was taller than Taylor at the time.
And I don't even want to think about what would happen if two people got sick.
*The Cow is a simple (but evil) part that could easily be filled by Alayna but no understudy was officially designated.