Whispy Woods' acquired ship piece could probably not be his fault. When they were flying through the air the oars could have landed in his branches. He attacks Kirby on sight because he doesn't like him; and when he is beaten and does a Chain Reaction Destruction it knocks the piece out of his branches.
The Plasma ability's merged with the Spark ability in this game. This isn't much, unless you realized via a Genius Bonus that Electricity's made up of plasma. Thus, Plasma ability merged with Spark the same way Burning merged with Fire and Freeze merged with Ice.
It's already circulated that the first letter of each world's name spells out the word "CROWNED." But there's another little layer to it. At first, even if you notice it after the first five worlds, then you'd think it's just foreshadowing the prominent crown atop Landia's head. Then, as the level moves onto Egg Engines and Dangerous Dinner, you realize that with that pattern in mind, it's not spelling simply the object, but a word used to signify someone already has it. And with an all-star hero like Kirby leading the way, the crown was already as good as Magolor's.
During the fight with The Lor Starcutter, it fires stars, launches oars, releases a whirlwind, and attacks you with boomerangs. What does it use to do these things? Its emblem, oars, mast, and wings, respectively. The same ones you had to collect. Yeah, that's right, by collecting all those parts, you essentially weaponized the Lor Starcuttter.
Look closely at Magolor Soul, particularly his center. With his mouth exposed and without his trademark robes, he looks less like Magolor's normal form and more like a demon- (or worse, Zero-) possessed Kirby. Also keep in mind that despite the name, Magolor Soul is a manifestation of the Master Crown, not him. If, say, Kirby had put it on instead, then he could have turned into that abomination, if not something even worse.