Nice work there. I am wondering about some of your things.
First, I like the license plate mount but it probably needs more support in the form of another leg of tubing on each side. Also I would paint all the supports flat black to make it appear the plate and taillight are "floating."
Second, I like your battery hardware -very cool.
Third, your rear brake actuation. I can see lots of work and care put into it but am concerned that a "pusher" rod actuator isn't going to be the strongest and may flex instead of providing stopping power. I would probably remount the pedal tab on top and run the connecting rod either around or through the lower frame member. Or also flip the hub lever up so that it connects straight.
Lastly, I like your exhaust solution!