I'm willing to forgive the merchant (though I was originally of the mind it was the same merchant from 2.0's opening and 2.55's ending, and that he was more important than initially assumed), but I'm not a fan of trans-dimensional doppelgangers. Having doubles beyond minor, low-key NPCs kind of ruins the whole "other world" feel Norvrandt is supposed to have.

Then again they all still speak the same language with the same accent despite ~12,000 years of divergent history making that nigh-impossible, so I guess it's not too surprising...

Maybe Urianger is calling Y'shtola "Master Matoya" by that name in the OP because it's not actually her, but her double...