Well actually since I mentioned it, why not. For the record, I know some of these have people cast for them already, this is just my list, who I would have picked. Also I didn't do all the characters each person had nor characters from all people. I just did some that came to mind.
Raptor's Characters:Nightmare- Played by Bill Nighy
The Good Doctor- Played by Julian Richings
Aurelia- Played by Jaime Murray (She's been known to play roles involving altered skin and hair color as well as non-standard outlooks and done them extremely well so would be my first choice there.)
The Cancer- Played by Clint Eastwood (If he ever gets a sheet you will know why.)
Neutral Nexus' Characters:The Cowl- Played by Eric Roberts (This guy plays a classy but corrupt blackmail style criminal villain like he was born for the role.)
War Pulse- Played by Tom Cruise (Badass character, badass actor. Enough said.)
Umbraxis- Played by, sorry have no idea here.
Nightmareshape's Characters:Forsaken- Played by Benedict Cumberbatch (Came to mind almost immediately. Was brought to mind by his job in the Star Trek film.)
Icon- Honestly, you picked a pretty good one yourself don't really have one for this who I thought was necessarily better.
Dedonus' Characters:The Iron Knight- Played by William Fitchner
Athinar's Characters:
Equilibrium- Played by DJ Qualls (The perfect mixture of awkwardness and determination in most of his roles.)
Kalistar's Characters:
Radiance- Played by Kristen Bell (This may or may not be due to her role as El from heroes but electrical powers seem to go very well with her.)