The size of the skeleton is important. Lloyd would be about the same height and proportions, just with a smaller head. And the sword is actually just as important as the skeleton to the model, so I would think it would have to be a sword user, otherwise they would have used Brawler or Gunner. We're basically looking for a sword user that stands at about the same height and has similar proportions as the miis. That's pretty definitively Lloyd. You're right that it's speculation, but imo it's still pretty damn convincing after what happened with Duck Hunt and Banjo.So this is indeed speculations... not so far-fetched, sure, but still speculations anyways. Who knows the many reasons wich could have cause this glitch. Maybe it's true, but I don't want to rely my hopes on that.
Miis have really plain skeletons, so I would think it could be anyone, even a character who doesn't wield a sword but would have similar stances or movements.