Not so sure about the seaweed thing, as
Karxrida said they could be referencing the Leafy Seadragon which Kingdra was based on before the Skrelp family. Besides being this is the Pokemon world maybe one day there would be a straight up Seaweed Pokemon.
Not the first time they hinted at a character possibly wanting to commit suicide. Remember the old man in Anistar City who you give a weak Pokemon to to keep him company in XY? There's a hidden Escape Rope nearby the house which many has taken as being from the lonely old man. And as for general darkness, some have taken the Antidote found in the trash in the Old Chateau in the Gen IV games as possibly meaning the people who lived in the house were poisoned. And then there's Sea Mauville.
Maybe N didn't give his name? I imagine N just swooping into the Gym, challenging the Gym leader, beating them for the Badge, and leaving not really caring to be "honored" by his name being printed on the entrance plaque.
And maybe N wasn't recognized as Champion since he kind of tried taking over Unova and I would think that would disqualify you. That or he never entered his team into the Hall of Fame, can't be Champion if you're not in the Hall of Fame. Or N could be just A Champion while Alder is still the League Champion, but we've already opened up that can of worms with Steven in ORAS.
U-turn's Japanese name is "Round-trip". Actually from other sources it sounds more like it's suppose to be translated as "somersault" which in Japanese is called "dragonfly return". Once again, like with Aerial Ace, the pun is used to give it its Bug-typing, however the meaning is still there. The Powerless Man was thinking of committing suicide by jumping off the balcony, but his mind somersaulted the idea and he never went through with it.
Actually it seemed implied that the reason Cheren, Roxie, and Marlon became Gym Leaders is because the Striaton Trio, Lenora, and Brycen quit. Though that could just me reading into too much of the meta. Afterall to participate in the Indigo League you either need the Kanto OR the Johto badges (and the anime seems to imply you can mix and match them, though the anime also says there are WAY more Gyms that we never see except for their Badges).
Actually, that sounds like a fun topic.
What types do you think these badges came from?