A little late to the party with this thread, but thank you for sharing your ideas with the lighrs running off the motor.
I read a lot of negative comments, and the opinions suggesting I’d end up with an explosion the size if Chernobyl if I decided to replicate your idea.
Anyhows, I decided to take a positive approach coupled with a bit more research. I found in the Bafang tech specs that the light output is rated at 12v and 12w, and there is separate feeds from the motor for the front and rear lights.
I found the genuine Bafang cables on eBay for £20 that plugged straight in, I bought some lights off Amazon for £30 that are correctly rated and powerful. All wired in and working perfectly, basically did the same as you did in your video so thank you for the post, it was most helpful.