Will my music have a delay through the A2+ Wireless if I’m watching a movie or music video?

Though overall latency can be affected by some external factors (including but not limited to signal strength, and even simply being physically further away from the speakers), Bluetooth on the A2+ Wireless generally has a delay of about 30ms (milliseconds) so you should be able to watch videos from Youtube, for example, and stream out the audio to the A2+ Wireless without any significant or noticeable lag between the video and audio.