Because Adeleine and Ribbon have different origins, there originally wasn't really a reason to pair the two together, although I've seen exceptions. They are the only characters from 64 that did not make future appearances for the longest time. Even if Bandana Dee isn't the one from 64 I bet the latter Dee appeared in Tilt n Tumble and Canvas Curse, but the female teammates did not show up in anything for over a decade.
As a playable character, Ribbon compliments Adeleine's shortcomings pretty well, so I can see why the duo has become quite popular. I don't personally like or dislike the pairing, but I think in future it wouldn't hurt to separate them a bit. Maybe Adeleine can give you items again and Ribbon can act like that angel from Epic Yarn and save you from danger.
I don't think Waddle Dees are meant to be specific characters... HAL seems to consider Waddle Dee as a species in general more than as a specific character, so it doesn't really matter if the K64 one is the same or not... it's kinda like Yoshi in Mario, or Toad... there are multiple of them and it's not important if that specific Yoshi or Toad you meet in a game is the same you meet in another.
Anyway, I see a bright future for Adeleine, Ribbon and all the characters from the Dark Matter trilogy who have been neglected for so long.
They are appearing in promotional stuff and merchandise, HAL seems to have finally accepted them and I'm sure we'll see them again and again, even in future games.
On the subject of the "couple", I like them together, but I also don't mind Adeleine alone. I'm not a big fan of Ribbon alone because I think she's a bit limited since she doesn't seem to have any fighting skill... as an NPC she could work well though; my only problem is that she's supposed to live on a different planet so she needs an excuse to be there... but if you pair her with Adeleine, the excuse might even just be their friendship, no need for futher explanations.
After all, the idea of Adeleine & Ribbon being a duo character similar to Cream & Cheese in Sonic, isn't that bad IMO... but I'd like if Ribbon was more involved in the moveset than just fly and crystal gun (the cutscenes of Kirby 64 have shown some more interesting powers of the crystals that can be adapted to gameplay).
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Now to change topic:
While looking at some posts on the Kirby subreddit, I have found this link with an interesting analysis of the Ado/Adeleine thing.
https://kaialone.tumblr.com/post/182877726465/kirby-translations-ado-adeleine-the
I don't really agree with the speculation part, I don't think they wanted to leave it completely open at all, I think they heavily implied that Ado and Adeleine are the same character, so even if there isn't an explicit confirmation yet, it's pretty obvious that HAL is considering them to be the same, and making up theories that say otherwise is just overcomplicating and overthinking (dataminers even discovered that she has been internally referenced as Ado in the source files of a game, it was the title of her song in Fighters Deluxe or Team Kirby Clash Deluxe, I can't remember now; and there's Ado's Painter too).
Though the article is interesting regardless.
The fact that Adeleine calls Kirby with a nickname (that IMO shouldn't be translated with a meme -.-) is funny and matches with the Ado nickname thing.
It's nice to find those small details about her personality when so little is known about her.
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Final part of the post:
the color thing...
For the 27th anniversary of Kirby (I'm not sure though), HAL published a video on Twitter. It's very cute, especially the part when all the characters throw the heart following the rhythm of the song (makes me think of Rhythm Heaven!)
This video is odd though...
I mean, everything is normal, except Adeleine.
Why did they change Adeleine's color? Why is she more yellow-ish than her recent redesign?
The color shown in the video is very reminiscient of Ado's version of the character. It's basically the shade of green she had in the credits of Dream Land 3.
It seems that they purposely applied a filter on her, and only on her... (is especially noticeable because in the same scene she appears in both colors, it's so obvious that they edited it).
During the victory dance scene, she's still of a different green, but a darker shade; everything seems to have a slighty reddish filter here but Adeleine still has a more yellowish shade of green than usual, it's not her normal color; it looks different than the other one too, as if the filter applied here is even different.
Then, in the HAL logo scene, she's back to normal.
So why did they edit the colors of this character specifically? Is there a reason for that?
I don't know the actual reason for this, but it makes me hope they are still working on the character (similar to when they changed Metaknight's eyes from white to yellow) because they still have plans for her. I hope this means that they will feature her in more games from now.
Or maybe they just wanted to reference how in the previous games her design changed several times even in the same game