But I agree that it would be hard to come up with a moveset for the Journeyer. Wander makes a lot more sense as a fighter though.
Square = Scarf attacks
Triangle = Symbol attacks (Such as summoning those floating things to help)
Circle = Music attacks
I haven't played Journey, but I could think of that stuff. Since I've yet to play it, though, I can't really say whether it'd be hurting Journey itself if the Journeyer was in, or what specific things could be for moves and/or supers. I'd be perfectly fine with a stage and an item from the game as representation, even though the Journeyer seems to be an icon in a way.
I want it/him/she. I mean Sackboy is in the game and its not ruining LBP's image
LBP is about creating and sharing, and just having fun. Journey is literaly about the journey. I gurantee any move you give him would be a contradiction of his charecter and for a game developer that strives so hard to honor source material this would be nothing less then unaceptable.