I'm starting to think that the "oddly written" subtitles have something to do with it. Think about it:
Red Alloy! He’s not the leader or anything!= Leader may refer to Captain, obviously he ain't Captain Falcon.
Blue Alloy! For some reason she seems kind of gentle.= Sakurai notes her odd gentle appearance, this may be in purpose to follow the Alloy's similar structure of Zelda with her obvious amiable and docile persona.
Yellow Alloy! Those horns are scintillating!= Through scintillation he may refer to glowing similar to the compliment, "You are glowing!". Furthermore, Sakurai emphazises the horns. This may be in reminiscince of one of his recent and rather forgotten puzzle games, Meteos, where the glowing and horned characters made their arrival.
Green Alloy! It may look like Kirby, but it’s not him!= Many people are assured that it's Kirby, but throughout strongly stating it's not Kirby though it looks like him, he may be referring to the return of the nearly identical Jigglypuff.
Sakurai may be using the alloys to hint the recurring arrivals of two characters. But I'm slightly doubtful of my Yellow Alloy conclusion. But I don't think anybody can really joke of these ideas. Overall however, I really don't care if these theories are true or false.
Hmm nonetheless it's an interesting idea!
