OCB, on an earlier Trilogy list (from Marz.com I think), it listed further ROTK waves next year which included many of the figs you're hoping for, with the exception of Denethor and Mouth of Sauron. Personally I think those two and a Gondorian Knight are also in the cards. The fact there isn't a Gondorian Knight already is more evidence of Toy Biz's hit and miss planning.
I hope my TW Frodo doesn't show up anything other than minty-mint for the price we paid for it. I'd be upset if I were you, HMI.