So, am also looking for an Arduino or two with Bluetooth and WiFi capabilities in Stereo Headphones. The exact function of the headphones is something I don't want to discuss on a forum but definitely looking to make custom headphones for myself and my wife.
The Arduino may not work for you. The regular Arduino doesn't have a DAC (no true-analog output). It can make square-wave tones, but that's probably not what you want to listen to. It's also not fast-enough for continuous Bluetooth audio and the built-in memory is too small for "useful" audio.
DVDdoug, thanks for the input!
The ESP32 has a fast processor with built-in Bluetooth. It's not an Arduino brand board but you can add support for it to the Arduino IDE.