Possible Clues:

• Pop star's assistant
• Noel Gallagher once worked as a ____ for Inspiral Carpets
• Tour employee
• Worker in the gig economy?
• Travelling crew-member thus could be authorised for reassembly
• One working for Kansas or Alabama
• One handling 4 down for travelling entertainers
• Band entourage member
• Tour crew member
• Writing circle contacts most of those in 21 across for helping the group get set up