On the subject of the hat thing, I think I mostly agree with
Shadow Keebey
and
Sailor Waddle Dee
in the sense that giving him different hats without his bandanna to reference multiple Waddle Dees could muddle his identity for non-fans, and potentially give them the impression that he isn't an individual character, but rather a generic amalgamation of different Waddle Dees. Especially if they do go ahead and simply name him "Waddle Dee."
While the different hat idea does sound kinda neat, I think I honestly would prefer recolored bandannas as well, as it would let Bandana Dee retain his signature accessory, while still having cool references, like a blue and white bandanna to reference Sailor Dee like Keebey said, or a white bandanna with green stars to reference Cleaning Kirby's bandanna in Star Allies. It would be a lot like Dedede having different patterns on his sash for some of his alts, and Meta Knight having the vertical slit painted over his mask for his new Galacta Knight inspired alt.
...though if he had a hat for just one alt, then it might not be so bad. And if he did, then my vote goes to the Cafe Waddle Dee hat!
Aaaaaaaaaaah, just look at it, it's sooo precious! (Plus, he could even wear his bandanna underneath it if need be!
That being said, I do think that if he were named Bandana Dee/Bandana Waddle Dee, then
Lisbon Mapping
's idea could be pretty cool to represent the 64 Waddle Dee, since it would have the name difference and different weapon to establish that this is a different Waddle Dee. The problem then, however, would be that any one unfamiliar with Kirby 64 might be confused about who this regular Waddle Dee swinging a crystal around is, and not understand the significance of it given his lack of a proper name. Still, could be cool.
However, I know that it's yet to be confirmed whether or not these two Dees are one and the same, but I actually would really prefer an alt for Bandana Dee where he still has his bandanna, but he's either wearing the crystal necklace like
PhilosophicAnimal
suggested, and/or has a crystal shard as a spearhead. To throw a bone to the headcanon y'know? ...Or better yet... confirm it... (Man, I really would like it if HAL could confirm whether 64 Waddle Dee and Bandana Dee are the same person or not...).