It does say "Main Feature Audio: Dolby TrueHD: English 5.1" but I can't find information on the cast or anything so it might just be copy/pasted from other BDs.
I think the issue with dubbing any music anime is the music. You either keep it in JP or dub it, neither of which is very optimal. Due to differences in industry you often aren't going to find suitable replacements of the same quality for the vocalists, and leaving it in JP is hella awkward and immersion breaking. It's a pretty big lose lose.