While I'll wait to the 9th's announcement to decide whether these leaks have any merits, it never hurts to play with the idea suggested:
Version Exclusive Champions: Sounds like a fun idea and I would be all for it. It'll not only place Red & Blue in the canon as NPCs (instead of simply being replaced) and a nice if obvious reference to Yellow Version. Though if this is the case, while Red will certainly have a Pikachu, would Blue have an Eevee or would he evolve it into one of the Eeveelutions? And if so, what would be the factors that decide what it'll evolve into? Though if they're the Champion, that'll surely mean this takes place after the story of the Gen I games, so what would this mean for Giovanni (not that they can't write around it... or ignore it... but I'd personally like some continuity)?
Beyond Evolution Episode: Not really an "episode" but what you would expect them to do for the post game or New Game+. Though that mention of Mega Evolutions for important faces. If they mean Gym Leaders and Elite Four, some Types are missing: Rock, Electric, Ground, Ice, and Fighting (I doubt they'd give Bruno a Mewtwo). On top of that only Sabrina and Agatha have their signature Pokemon with a Mega Evolution. Now a solution for this is just only having the rival and Champion having Megas and maybe some other random trainers, though that would be pretty boring. And sure, if they do make new Mega it'll be for Gen I Pokemon, at least it'll show they didn't forget about the idea and maybe the Gen VIII games will reveal Mega for other gen and the ones in Let's Go were a sneak peak.
Little Pink Whale: ... HSOWA? Aside being a new Pokemon I have no clue what this could possible mean. Notably it says received from GO, unlike the "new Pokemon" they've hinted at in the past which is a gift directly to the Let's Go games. Unless they are the same. Well if it is a new Pokemon, hoping it's not a "little whale" but rather a dolphin/porpoise.
Color Charm: As in increased the chance of encountering Shiny Pokemon, aka the Shiny Charm? Or is the game going to do an idea they did in the original Stadium game where a Pokemon could be slightly different colors from the base. That would certainly be a surprise, though kind of stinks you'd need to wait till post game to see this instead of something being active and the charm only gives you greater control over it.
Multiplayer Costumes: I imagine this is something similar to what other games have been doing with player avatars in the online hub such as with Dragonball FighterZ (or, you know, other Pokemon games that let you pick a Trainer Class to run around as in multiplayer). Personally would rather they just be costumes though I can also see players wanting to run around as the character instead of dressing the default trainer as them. So, what are all the possibilities:
- Gym Leaders: Brock, Misty, Lt. Surge, Erika, Koga, Sabrina, Blaine, Giovanni
- Pokemon League: Lorelei, Bruno, Agatha, Lance, Red, Blue
- Notable NPCs: Playable characters, Trace, Professor Oak, Mom, Mr. Fuji, Center Nurse, Mart Clerk, Bill, Old Man, Safari Zone Warden, Copycat, Pokemon Fan Club Chairman, Gym Guide; there's other the notable NPCs added in FRLG: Daisy Oak, Primo, Celio, Lostelle, Teala
- Trainer Classes: Team Rocket Grunt, Youngster, Lass, Hiker, Ace Trainer, Beauty, Biker, Bird Keeper, Black Belt, Bug Catcher, Burglar, Camper, Channeler, Cue Ball, Engineer, Fisherman, Gamer, Gentleman, Juggler, Picnicker, Poke Maniac, Psychic, Rocker, Sailor, Scientist, Super Nerd, Swimmer, Tamer
On top of that, would there only be one model for them or would they maybe give some clothing options to choose from. Like Gym Leaders/Elite Four having clothes they worn in other games and Trainer Classes having different set of clothing (mainly palette swaps).
Joycon Move: If they wanted to implement Z-Moves this does sound like a rather unique way to do it. Let's remember, these games are for kids and for most of the experience they'd be sitting down. So what better way to get them to do a little exercise by performing the Z-Move poses? Would probably have to simplify some motions, or just have any motion count and not expect the kid to know that (and not make the adult players having to jump around), but I could see it working.
Otherwise don't know what they could be besides just boosting a move's power and giving it a flashier animation.