Hookbill would be
Matt Bellamy (Muse)
The Saucepan Man would be
Ringo (The Beatles)
The Phantom would be
Josh Homme (Queens of the Stone Age)
Gil-Galad is
Billie Joe Armstrong (Green Day)
Boro88 is
Ben Burnley (Breaking Benjamin)
Orominuialwen is
that girl from
Flyleaf
Enca is
Shirley Manson (Garbage)
Estelyn is
Nancy Wilson (Heart)
The Barrow-Wight is the
Knight of the Round Table who sings
"I have to push the pram a lot"
Fea is
Stevie Nicks (Fleetwood Mac)
Nilp is
Freddie Mercury (
Queen)
Meela is
Cher
The Guy Who Be Short is
Gerald/Gerard whatever Way (My Chemical Romance) except Guy can actually sing.
Mormegil is
Maynard James Keenan (Tool, APC) except considerably less insidious.