Heyyo, I'm back to share my ideas. As in a similar boat I didn't actually watch the full movie, I decided to spoil it for myself and enjoy it in bursts. Fsr I'm weird about movies.
I wanted to pitch Wart and his Minions from Doki Doki panic. Or Mario Brothers 2/USA as it would later ne known. It introduced many enemies and creatures still in Mario to this day, like The Shy Guys, Pokies, and Bob-ombs.
In the Game's Story, Wart, a demon/Nightmare frog king and his minions kidnap the citizens of the dream world Subcon, and Mario, Luigi, Toad and Peach team up to rescue them. Though it's later revealed to all be in Mario's dream.
Obviously there's Wart, the main boss and leader. He spits hazardous bubbles like an opposite element to Bowser's fire breath and his weakness is vegetables.
There's Mouser, a bomb throwing rat.
Tri-clyde, a three headed fire breathing serpent.
Clawgrip, a boss unique to Mario 2 who wasn't in Doki Doki. He throws rocks.
And Fry Guy, a living fire elemental.
However out of all the bosses from Mario 2/Doki Doki, a certain reoccurring Midboss is the one who became the most popular. And is still a prominent member of the cast. One of video gaming's First Transgender Icons:
BIRDO! The Egg Spitting Dino Diva!
Now even though her first appearance is as a reoccurring Antagonist. Nowadays Birdo is actually a friendly Neutral or hero character with a flirty personality. While descriptions in the 80s and 90s described her as "A guy who thinks he's a girl". Birdo's gender being female is Nowadays respected and her Trans status is not treated as a joke anymore.
One thing I find interesting about her is that her Romantic intrest and best friend from the N64 and GameCube era and possibly onward is Yoshi. The two being an item since the first Mario tennis.
Now... in your AU Yoshi and DK are more animalistic. And I assume the same would go for Birdo if you were to bring her in. And I mentioned taking inspiration from the movie for my idea. So here's my pitch.
In the movie, after Princess Peach beats up Wart and his underlings, he gets upset and vows vengeance on Peach. While at the same time, he chokes Birdo, incases her head in a bubble, and angrily barks at her to warn Bowser Jr. As if he's the kind of boss to take his anger out on his minions. And with it being Birdo specifically in that scene and knowing that she's usually a good leaning character every other time I've seen her... I kind of think she should eventually switch sides after dealing with Wart's abuse.
My pitch for your au... is that Wart could be a crime boss who keeps exotic and dangerous creatures as pets. With Mouser being his right hand man. Tri-clyde, Clawgrip and Birdo would be his pets in this instance (not sure about Fryguy yet) and when Mario and Luigi encounter them... they witness Birdo being treated poorly by the cruel frog. Perhaps Birdo is actually quite gentle and just scared and lashing out because of her treatment and the Brothers decide to show her compassion and bring her home. Surprisingly, she and Yoshi bond and end up becoming close. Like a cat and a dog who become cuddle buddies if that makes sense.
Idk if it fits the vibe of your au... but Birdo is actually a Mario character I find really neat. And I find her relationship with Yoshi very wholesome. Her diamond ring is sometimes brought up in the Yoshi Tax Fraud memes which is really fun lol.
Hello hello! :D Sorry I'm so late to respond to this- life got awfully busy and then the TADC leak happened and then Art Fight preparations.. but no matter! I'm here now and ready to respond :)
Now, Birdo is already in my AU- let me explain. The Birdos are meant to be a coastal sub-species of Yoshi's. Just like how tigers and lions are both "cats" but look and live so different, and live so far apart.
Unlike their forest-y counter parts, Birdo's live nearly exclusively by the ocean in Daisy's costal kingdom. They're meant to be like flamingos where they start out pale, but turn pinks and reds after eating loads of cheep cheeps through out their life. I considered that Daisy had one as a pet, but I'm back and fourth on that now..
Now, I wont be doing any trans plotlines with Birdos since they're basically animals.. but what I could do tho is make the bros visit Daisy with Yoshi for a mini vacation or something. And while there, a female Birdo kind'a "chooses" the bros Yoshi as its mate of interest and begins to follow him everywhere. Yoshi doesn't really mind or understand.
At the end of their trip, this Birdo follows Yoshi and kind'a refuses to stay behind at the beach. And so they just.. take her home. XDD
For Wart and Mouser though? Your pitch seems to fit decently well into my AU :0 They could be some nasty criminals who deal with exotic animals. Not necessarily dangerous ones tho- just rare ones that are illegal to capture and sell..
Now Tri-clyde is interesting. That could easily be this huge snake-like species that roams on DK island or even Yoshi's island. Maybe its something Mario and Luigi encountered once.. 👀
Clawgrip could also be a species of large crab that invades Daisy's coast from time to time :00 Fry Guy is a bit different though.. "A living fire elemental" you say? I might make him one of a kind. I wonder what his lore would be.. some kind of ancient fire spirit? One of Kamek's recent spells gone wrong? Hmm...
Its a lot to think about. And thinking I will be doing! Since my Mario AU is always kind'a on my mind <XD I never really fully stopped developing it tbh..
Anyways- thank you very much for this ask! :DD And I'm sorry it took me so long to get back to you.. <XD Have a great day/night! :}}}}