Forum user Bigbadcloud has brought to our attention that one Twitch streamer has discovered that the English voices are still in Kingdom Hearts 2 in the theatre mode.
Bizkit047 made the discovery at the end of his almost 12 hour long stream when he was browsing the Theatre Mode. Accessable by pressing "L2", fans can view the HD cutscenes in English. You can view the footage on the stream here (starting at 11:50:10)
Kingdom Hearts HD 2.5 ReMIX will be released fully in English in December 2014.