Mmm casting discusssions...
I could totally see Christian Kane as Kincaid. He's got the right combination of size and menancing potential.
My rough thoughts (for now);
Harry - Torn beteen Hugh Jackman and Nathan Fillion. They both are excellent actors, bot Hugh doesn't seem have the right snark factor and Nathan doesn't ahve the hair...sorry to say it but I've always seen Harry as having longish and curly hair which Hugh can easily pull off.
Murphy - Michelle Pfeiffer ? Right size, can be scary looking when she wants to...
Thomas - hmmm any number of pretty boys could fill that role, Brad Pitt is an excellent actor but he's Brad Pitt and it's hard to hide that for anything. Johnny Depp could do it; he has the ability to hide himself in his roles.
Butters - Sharlto Copely (District 9 & the A-Team) he cna do humor and he can do serious...
Michael - Jeff Bridges ?
Charity - Jodi Foster ?
Molly - Allison Hanigan ? she'd be so adorable in that punky hair...
Rashid/Gatekeeper - Morgan Freeman ?
Merlin - John Malkovich ?
Leahansidhe - Helen Mirren !
Ramirez - John Leguizamo!
Ebenezer - ? I so have an image in my head of someone appropriate but I cant think of where I've seen him. Have to ocme back to this one tooo