Thanks for the report. I've heard some weirdness about Metatron there, will try to sort it.
Yeah, I'd like to add a few more characters interacting or at least showing up during exploration. It's fun, flavorful, and adds a sense of life to things. Could even have 'em stick around for a surprise battle or something; I don't want to make the game 3+ character parties, but in some situations it'd make sense to have it happen.