A portion of a Game Informer interview with director Kenta Motokura and producer Yoshiaki Koizumi...
GI: Mario's new has is named Cappy, but where does he come from? He looks like a ghost or something, is that correct? Is he like a hat-spirit?
Koizumi: We're not ready to reveal a lot of Cappy's backstory or secrets about that character, but he is going to be Mario's companion as he travels around all these different kingdoms in this title.
GI: We also ran across Captain Toad in New Donk City, and it was fun to see him. It seems like you guys have a fondness for him as well. Do you hope to do more with him in the future as well?
Motokura: Well I'd certainly be happy if you were looking forward to the possibility of a future Captain Toad game, but none we can mention just yet. But, Captain Toad is also an adventurer, so he will be wandering about in different kingdoms of Super Mario Odyssey.
GI: Why does Mario want to stop the wedding between Peach and Bowser. Is he interested in Peach romantically, or does he have some other motives?
Koizumi: I've always thought that Mario carries a bit of a torch for Peach. I think that's true even back in the 2D Mario games. If not, he wouldn't be wasting his time rescuing her over and over again.
GI: Do you think Princess Peach feels the same way?
Koizumi: The heart of a woman is a mystery.
GI: In Super Mario Galaxy 2, there was a throwback Galaxy level that was a remake of a Nintendo 64 level. Will there be any throwback levels in Super Mario Odyssey?
Motokura: We don't have any levels that are taken, let's say, specifically from something like Super Mario 64, but we do have elements in the game that will make the folks who played Super Mario 64 happy when they encounter them.