Not bad. I'll see your Elizando and raise you Ken Watanabe
As for the other New TCats, I'll take Michelle Rodriguez as (the criminally underused) Pumyra
If I may say, finding the perfect actor to play Bengali is nigh-impossible. That said, I think Penn Badgley could do a good job.
Casting the Mutants is a bit of a challenge, but it also allows one to go a little crazy, since casting monsters is a very inexact science.
Lee Arenberg (PIRATES OF THE CARIBBEAN) as Slythe
Seriously, he looks like Slythe's human twin!
Dash Mihok (PUNISHER: WAR ZONE) as Monkian
He also played (or mo-capped) the Alpha Male in I AM LEGEND, so he's got that going for him.
For Jackalman, how about go-to thug character actor Kevin Corrigan (THE DEPARTED, PINEAPPLE EXPRESS)
For Vultureman, I'll take Mackenzie Crook (Pirates of the Caribbean, "The Office)
And for the grand finale:
Michael Clarke Duncan as Grune the Destroyer, of course
That's all for me as far as casting THUNDERCATS. Guys like the Lunataks and the Berserkers, someone else can have them