Pumpkaboo is eh. One thing that helped make Marshadow viable was Prism Star stadiums and Chaotic Swell being both a thing while it was legal, on top of freeing its bench space for more useful cards later on. If you want to stadium bump post-rotation, well, just run a stadium yourself. There's gotta be one that helps your deck. Bench space is THAT important. At least it's searchable.
Gourgeist is Sandaconda but worse. You specifically need Twin Energy, Triple Acceleration Energy rotates, and you could even end up unlucky and hit an energy on those discards. Maybe if they reprint TAE it could be a fun meme deck, but otherwise it fails from inception.
Swap Cup is OK, but until Oranguru rotates it won't warrant use. Yes, Oranguru uses a bench space and is prime Boss bait, but it's reusable and searchable by Quick Ball.