Yes, apart from the "Chamber of Secrets" they are identical, indeed. I don't know why they chose to translate it with "Kammer des Schreckens". It's not as if we didn't have the word "Geheimnis".

"Becher" sounds too mundane to me. A "Kelch" should be slightly bigger. When I hear the word "Kelch", I think of the goblets people used at banquets in past centuries - made from (noble) metal and possibly studded with diamonds. [The goblet used during the sacrement also is a "Kelch" and not a "Becher".] In contrast, a "Becher" sounds like a mug made out of clay or porcelain to me.