Speaking of Yo'ster Isle, there's that blue yoshi there with the spiked collar and Kamina shades, right? In the original Japanese he was "Washi", a spin on the Wario evil twin idea, but was localized as "Boshi", presumably a portmanteau of "Bad Yoshi".
Yoshi is my daughter's favorite fictional character. She has a big green Yoshi stuffy, which she calls... Yoshi. So when she got another, smaller purple Yoshi stuffy, she decided for reasons she has not explained to call it "BoshI". I haven't shown her this game yet, so I don't know where she got it.
Anyway. I can get to Monstro Town, where the key on the cliffside that you can get after convincing a Thwomp to shake it down for you is replaced by the Tenor Card. The shop at Tadpole Pond carries Megalixirs now, for pretty cheap, so if I ever run into a spot where I can't keep up with healing I have a solution.

Moleville sells Sticky Gloves, which both Mario and Peach can use. I still don't have Mallow, but when you attack with a weapon that a character normally can't use, the game loads in the animation for that attack by the character who normally uses that weapon. So it might look like I shuffle my party around and even get duplicate characters in later screenshots, but no. It's just the weapons I've managed to scrounge or afford.

Croco in the mines is replaced by Jonathan Jones. Once I use the Bambino Bomb to open up a wall and proceed to the end, I find that Punchinello has been replaced by...

er, Punchinello, this randomizer sucks

Fascinatin' bit of cake decoration you're doing there, guys.

For a game that remove most of the cutscenes and dialog I'm a little surprise you still have to hunt down the Snifits for all of Peach's fashion accessories before you can fight the Marrymore boss. You don't even get the cutscene unlocked by retrieving them!

Anyway, as the sneak-peek in the kitchen hinted, the boss is a chest mimic monster. I forget which one this is. Chester? Whatever. He gets chumped.

Hooray, I got the guy I basically never use in the vanilla game.