Zerth, I'll have you down as an alternate, but I warn you that it is far more likely that I would request an alternate take over one of the current charcters (tweaking it as they desire) than bring in a new character. Orshallan selected Low'verok's greatest champions and charged them with this quest, and he would be a little weirded out if the party came back with a bunch of new people. However, if things get bad and someone drops out, I might possibly see my way to killing their character and bringing another hero of Low'verok who originally wasn't going to be able to make it to the meeting in Andeluvay for reasons of his own.
As any rate, as one can see from the books available in the first post, Complete Warrior is not amongst them because I do not own it. If you would want to use something from it, you would have to e-mail me the particular contents in question. Eldritch Knight be possible, but I would gently request to look at one of the 3.0 warrior/wizard PrCs first (Spellblade, bladesinger, arcane trickster, modified war wizard of cormyr, or something from Dragon magazine). If none of those are two your liking, then go with the Eldritch Knight.