The ability mixes are back (and weren't gutted like they were in Squeak Squad)!
My dream game has a main story mode where Kirby teams up with Dedede, Bandana Dee, and Meta Knight again like in Return to Dream Land, but this time you can switch between characters at any time to solve puzzles or gain an edge over certain bosses. Strong winds you can't get past? Switch to Meta Knight. Need to break something blocking a collectible? Switch to Dedede. There's a boss who takes extra damage from Spear ability? Switch to Bandana Dee so you don't have to worry about losing your ability. That also means when you go multiplayer, player 1 isn't forced to be Kirby; that was one of my biggest gripes with Return to Dream Land's multiplayer. Besides, a switch mechanic would perfect for the new 2017 console - the Nintendo Switch.
This, Air Ride, and Super Star Ultra were my childhood. It'd be amazing to see what revamped copy ability mixes would look like or do, or to see Adeleine and Ribbon again. I mean, come on, the one measly cameo Ado/Adeleine got in Triple Deluxe, she wasn't even acknowledged! And Ribbon's practically vanished off the face of the earth.
I'm pretty sure Zero/Zero Two are the same, with Zero Two being the stronger form; he was also confirmed to be Dark Matter's leader. Dark Nebula was either the original Dark Matter leader before Zero took over OR, because of the whole "he's Dark Zero in Japan thing", a weaker version of Zero that Meta Knight trapped in a treasure chest to prevent his rising back to power. Necrodeus is probably on his, but I wouldn't be surprised to hear if Dark Crafter was Dark Matter or related to it. Dark Mind might be Zero's mirror side. That Master Crown, especially in Magolor Soul form, just screams Dark Matter, what with the crystal being part of an eye design AND giving Magolor a red eye. As for Gooey, before I knew any better, I used to have a headcanon he was Sword Matter reformed (the guy from Dream Land 2), since all he really wanted was friends and all...which reminds me, I wondered what happened to him?
I don't see why not, especially considering the Tornado Kirby page for instance still uses the artwork from Squeak Squad... which was released about 8 years ago IIRC.