PBR wasn't made by Game Freak, EeveeLv99 - it was made by Genius Sonority. Not that it matters, though - I'm pretty sure the dub announcer wasn't an employee of either.
I see no reason to doubt the anime when that's what we've been using as the guide for pronunciation of Pokémon names since the very start. Also, PBR was released years before Arceus was even a confirmed Pokémon, so I'd rather not trust the announcer in this case...
In Japanese, Arceus is pronounced with a soft C. In English and most other languages, Arceus is pronounced with a hard C. Why do people have a problem with that?