When you said you expected only four files to have noticeable localization issues, did you include the newspaper article on the Sewer Gators guys? I just checked the Japanese - not only does it not say they're urbexers - it doesn't even say they're big on haunted houses. Just that they do internet videos. Both sentences after Clancy's name are made-up. Even the newspaper headline is actually "3 Men Missing in Louisiana".
I also replayed the final boss fight. I was right - there is no subtitle for the "damn you all to hell" line, so I'll assume it's a joke one of the writers on Reichwein's team ad-libbed in and he as director approved of.