Updated it with Sushie. After analyzing the files, these are the prebuilt renders used for the Catch Cards, and are the only instance of the PM64 partners & Vivian in SPM. I'm guessing the idea that there were separate unused sprites of the partners excluding Sushie stemmed from this sheet being labeled as unused and Sushie being missed in this rip. There are unused rigs of the TTYD partners excluding Vivian in SPM, but they are entirely leftover from TTYD's menu models (which also did not include Vivian as she was the only one to just use her main model in the menu in that game). Some of those have been uploaded already.

I made a little chart illustrating my findings on partner models across both games. The "SPM has unused rigs of the PM64 partners excluding Sushie" tidbit is entirely false.
https://i.imgur.com/Pf12wsW.png

Actually now that I've analyzed the files, apparently the TTYD partners exist as animated models, left-over from their pause menu sprites in TTYD (since Goombella doesn't have stuff like her book), while all I can find of the PM64 partners are these pre-composed sprites. They do exist unused in TTYD, with separate parts though.

I tought this place was called the spriters resource, not the character render rseource.
Anyway why are there no indivdual parts?
Are the sprite sheets just not in the game?
Because if so, then i take back that first line of words in this comment.

Apparently they have individual parts, the complete images here are used for cards but the separate parts and poses are what's unused.

Edit: that was misinformation, only TTYD partner leftovers exist. The cards are the only place the PM64 partners exist in SPM's files

They were going to return in the game, but were scrapped.

weren't these used for cards