Can you be more specific on how Apple locked down Bluetooth LE? From my understanding it was accepted into the Bluetooth 4.0 standard in 2010 and has since seen widespread adoption in Bluetooth devices.
(MFi = made for iPhone) https://mfi.apple.com/MFiWeb/getFAQ.action#1-2 https://developer.apple.com/bluetooth/
Have fun with MIDI quality. The only way BTLE is sending mp3 or higher quality is through the MFi Hearing aid protocol Apple owns and keeps under wraps.