Did they translate "Stark"? Because it exists in both german and english but with different meanings.
No, you already said it, it's a word that exists in german so they kept it. It's obvious they really tried to keep as many names as possible, they were only changed when they almost jumped of the page and screamed english. I don't even remember family names other than the Greyjoys and the various bastard's names being changed, it's mostly locations and nicknames (Littlefinger, Hot Pie).