Hi and thank you for this great project. I have a 1500W ebike kit and it is pretty brutal in the power delivery so I am going to give this a go. The kit I bought was very cheap so I'm not surprised and have enjoyed doing small upgrades to it. I have ordered the parts you listed so will have to wait for a couple of weeks for them to arrive.
One other thing I'm very keen to do is to upgrade the cadence control as it's so poor as to be useless. I was looking for a way to do this with an Arduino and thought it might be something you could add to your project.