There is Donkey Kong (Playable) next to Donkey Kong (Not Playable). This shows you can have a playable character be a bg character. Instead of just going okay, it is POSSIBLE for a character to be playable and in the background (Not that Cranky is playable because of other factors that have deconfirmed him) you just arbitrarily say "artsyle is so different it doesn't count" You COULD have went with a better argument, albeit another arbitrary one, that this DK is actually young Cranky, but again, that's just fans nitpicking something that Sakurai obviously doesn't care about / didn't notice and making a rule about it. Youre, at the moment arguing against the idea that a character can be a stage element AND playable, but I bet on another day, you've argued Ridley can be a boss AND playable. (Maybe because they're different Ridley's like these Donkey Kongs are different Donkey Kongs)
They aren't the same character, though. I even said this when I said "the 8-bit incarnation of his
grandfather", so you seem quick to dismiss me as just another nitpicking fan despite me having said so little. Aside from being completely visually different in that their shape, artstyle, and appearance (I don't see a tie or a head swirl anywhere), they share only a name and nothing more.
Beyond that, were Cranky intended to be playable in the base game, why add the
one stage in the entire series that has what is undoubtedly Cranky Kong to the game? Past stages have remained untouched to this point, so there's no reason to think Cranky would receive a type of Alfonzo Clause in this stage. Even then, why would they have such a minor Alfonzesque detail if they're going beyond porting the stage anyway? Why not just remove Cranky outright so as to be more economic with the use of said programming? It makes absolutely no sense from a development standpoint to have him appear as normal until he's being played as on the stage, especially when it has no effect on the gameplay when seen through the same game design perspective Alfonzo was added for.
While I have argued that Ridley can be playable and boss at the same time before, I can admit to, I do not agree with my past line of thinking from before. The insanity I've seen in the Ridley thread has made me come to terms with that. If Ridley is shown as a boss, then that's it for him. It's primarily a matter of if the shadow we saw was playable Ridley's or not. The difference being, while Ridley's shadow is ambiguous at best, Cranky's shadow is two-dimensional and leaves no foreshadowing as a playable possibility.
Again, I'd rather go with Opossum's suggestion of keeping Cranky deconfirmed and digging him up if he does turn out as playable. There's no reason to suggest otherwise when every other character to this point has been deconfirmed under the same principles.