>Won't get a Nihilego (reserved for plot)
>Won't get any of the version exclusive UB's (version bias)
This leaves Xurkitree and Guzzlord.
Xurkitree has no recognizable face so it might not be a good idea as part of the team for character reasons, but it's pretty goofy already and it being an Electric-type might help it bond with Pikachu, or something.
Guzzlord, on the other hand, has the complete ability to emote. It also has some shenanigans with eating things, I imagine, but they could very easily look at it from the darker perspective and decide that it would be too dangerous to go with Ash.
