Aster also has 3000 atk monster (Destiny end dragoon). But zane is more fitting imo, since both ace card is some kind of dragon (cyber dragon and blue eyes) and has the evolution of 3 headed dragon (cyber end and blue eyes ultimate)
It depends what you consider Seto Kaiba's role in the original series to be. If it's just the main protagonist's main rival, no, that's definitely Chazz. But, like Kaiba, Zane (and a few other characters like Aster) he's a strong duelist that's been both an ally and antagonist of the main character.
Personally, I don't get why people try and label people as cross-series counterparts, but eh.
Well, both Zane and Seto have a younger brother, an ace LIGHT "Dragon" monster, a fusion monster which is made by fusing 3 copies of their ace card and a serious behavior. Not to mention that both get obsessed with winning after being defeated (and humiliated) for the first time (on screen).