So after a few months of talking about it I finally got a full run together for the proposed Super Hamsteak %, where you beat the game any% style, regain control for the extra turn and then lose with the Hamsteak ending.
The way I did it here took longer than regular any% and Hamsteak combined, but less time than the Talkshow ending. A big part of the challenge is getting rid of 2/3 characters during the main game with the hamster still available to pick up. Its about five minutes faster if you wait until the extra turn and use teledeath to finish the party from scratch, but that's not really what I had in mind and it gets complicated because of the "Hell Screen", where the other two characters aren't really there but can still respond to dying or using the Hunk-O-Matic. In any case, when I tried the post-game tele-death route the game spontaneously reset after the third "No Thanks" before the final graveyard, and so I don't think that would count as any kind of Hamsteak ending.
There's also the option of finishing the party during the main game with the graveyard overflow and beating the game as the ghost, but I feel like that is a separate thing even.
Lots to think about but i wanted to put it to you all that this is more doable than I expected. It'd be great to see some of you try to speed this up.