I know and have acknowledged elsewhere that as of this moment, Z.W.E.I.'s identity is unknown, but could be Grøh or Wilhelm at about an equal chance, honestly. Neither Grøh nor Wilhelm have as much in common with Z.W.E.I. as SoulCalibur V Nightmare did with Raphael, so it's a stretch either way. It's just a little frustrating to see a bunch of people fully on board with Wilhelm for similar reasons as where I was with Grøh except Wilhelm is apparently reasonable and Grøh is apparently not. I don't understand it myself. And yes, it's partly my own theory that whomever travels with Amy to Ostrheinsburg has a good shot of being Z.W.E.I., but that one seems a bit more credible than any other theory. Otherwise who is this guy and why is he important? We'll see either way whatever the future brings, but this is just me being a little obstinate given the circumstances I just mentioned.
Lucius could be a spear/shield user though, that's the more popular opinion of folks that are convinced Lucius has a chance, from my observations. His design is pretty fanciful for just a one-off, and unlike Maelys, he seems to have unique parts like Wilhelm, so I would say they're on pretty equal standing. Not that I honestly have much faith in seeing either of them derailing the train of waifus that is our DLC model, but Wilhelm is just as much a tertiary character as Lucius unless he does end up being Z.W.E.I., that's what I'm getting at.
I believe that SoulCalibur VII would have all four in Amy, Viola, Grøh, and Z.W.E.I. in that they'd start the game as the first identity and transition to the second identity by the end. The risky gamble comes in the next game, unless there's some explanation given where they could retain their original form somehow or otherwise had an adequate replacement, like if Viola had a daughter who took up the rapier or something like that (not that that wouldn't be contrived as hell, I'm just giving a possibility).
I will admit that Wilhelm does shake things up a bit, makes Grøh seem less likely, but at the end of the day, I don't believe we have enough evidence for either one of them to have Z.W.E.I. on lock, and I don't feel like Wilhelm has a real shot of being a future character on the roster. I could be wrong, of course, but I never claimed that my theories were absolutely true or infallible, contrary to Nyte's opinion. I have some cognitive bias in preferring Grøh over Wilhelm since it was my original theory, but I feel like Wilhelm has some problems fulfilling Z.W.E.I.'s origin story in being born and raised in a monastery, which I wouldn't describe Wolfkrone as, but the Aval Organization definitely could be, depending on your point of view. It's up in the air for now, and I'm just going to wait to see how the pieces fit in the future.