First Rhythm Heaven Headcanons post for one of the new minigames, and this one is for Alien Alphabet.
(Note, I TRIED to find the reading material for this level on YouTube, as I'm on a Google protest for privacy reasons and for the heck of me I wasn't able to find it, or any of the reading materials for that matter, so I'll have to hope someone eventually posts them all or unlock them by myself (however, I WAS able to find a video on all the comics), so if there's any contradictions in this post based on what the reading material for the level says, I'm sorry, I literally had no way of knowing when I made this)
First off, names, I already said the girl was named "Crystal" and the alien was named "Daar", and the boy, I've finally come up with something, "Kevin" was the name I went with for him.
(hi... Update time, since I made this post I was finally able to look at this level's rhythm reference as they're called... Overall, I got nothing wrong contradicted based on what I have written and what Nintendo had written, nothing EXCEPT the girl's name, apparently it's SUPPOSED to be "Shelly" and/or "Nao", idk, this is canonically written when the kids are much older, so I guess "Crystal" might be a nickname (although it is adorable that they confirm that Crystal/Shelly and Kevin get married when they're older โค๏ธ)
So, first off, Kevin is a genius, basically just Jimmy Neutron except not as malicious, Kevin can COME OFF as braggy but in the end he's just an all around kind kid who happens to be the smartest kid in Rhythm Heaven, the van seen in the minigame is actually just a really expensive toy van he bought for himself, however he created the real working alien satellite on top of it, Kevin usually uses this van to drive himself to school over taking the bus or walking, but most of the time, it's just to drive it out to where Daar is hanging out to chat with him.
Kevin is also Kii-Yan's (Toss Boys) older brother, the two siblings really enjoy each other's company, although Kii-Yan tends to not really understand some science topics Kevin throws around, he's still happy to listen, considering both were adopted by Beary and Bearbra from the Blue Bear minigame, I'm not entirely sure if Kii-Yan and Kevin are biologically related or not, but probably so, they look very similar, like aside from the glasses and the fact Kii-Yan only has the same hairstyle as Kevin when it's Toss Boys 2.
Kevin's biggest arch rival is Miho (Hop N Slide), she doesn't near match his intelligence, it's always just her being a bit of a jerk, but it has nothing to do with the fact Kevin's a boy and Miho's a girl, another difference between Kevin and Jimmy Neutron is that unlike Jimmy, Kevin isn't sexist, and that couldn't be more obvious when you see Kevin with his best friend, Crystal.
Crystal is very much the opposite of Kevin intelligence wise, she's a bit of an airhead, this never annoys Kevin though, it's like OG SpongeBob and Patrick dynamic, where Kevin and Crystal are amazing friends who almost never fight despite the amount of times Kevin has to explain obvious stuff to Crystal.
Miscellaneous: Crystal really likes the pop singer from Backup Spotlight.
Crystal is Aka-Chan's (Toss Boys) cousin, and since I have established that Aka-Chan's mom is Britney (Red Rap Women) and that she, Lucy (Blue Rap Women), and MC Adore (Love Rap) are all sisters, I'm gonna clarify that Crystal is Lucy's daughter, MC Adore is the only Rap sibling to not have any kids (currently).
Anyway, Kevin and Crystal are away from home a lot of the time, because they always want to go out and chat with Daar the alien, in the official comic for Alien Alphabet in-game, it shows Kevin and Crystal giving Daar some gifts only to end up hijacking his ship and joyriding it, to be clear, it was Crystal's idea and they landed and gave it back after about 5 minutes.
More on Daar, he is actually 12, he, Kevin, and Crystal are all near the same age range (Kevin and Crystal are like 9 or 10), Daar's planet's age laws just work very differently than Earth's, where even though age 12 isn't mentally grown at all, the species considers 12 to be a good age to go out and explore the galaxy by themselves (like how Pokemon journeys start).
Daar loves talking about stuff relating to the other space characters of Rhythm Heaven, the Space Dancers, the rhythm rockets, whatever is going on at Mars with the pork rice bowls, etc etc. He really loves hanging out with Kevin and Crystal because they actually understand his distinct alien language, Kevin actually having learned it on his own, and Crystal just naturally knew the language for whatever reason (still don't have an explanation for that)
Daar started peacefully living in Rhythm Heaven after meeting Kevin and Crystal, people may be familiar with him, but only Kevin and Crystal can truly communicate with him, Daar's still struggling to learn English, so he leans more into online ordering until he can figure out the language.
The events that led to Kevin and Crystal first meeting Daar were actually just the baseline events of the Jimmy Neutron movie if the alien the message ended up with was nice, Kevin sent out a message to space hoping an alien species would find it and Daar found it, not long later the first version of the minigame happened (yes, Kevin "canonically" doxed himself but everything ended up fine because Daar is friendly)
What do you think, what are your headcanons, and did I get anything wrong due to missing the reading unlockable :P