For those interested, the answer is - don't remove the fucking brake line.
I ended up having to pull the shrouds around the motor, feed through some fishing line that (miraculously) on the 500th try found its way through the motor area to the rear of the bike. In the process, I introduced some slack in the speed sensor cable and can't figure out where that was hiding (probably behind the motor?).
I've built all my other bikes from the frame out, so I'm no stranger to wrenching on a bike - nevertheless, trying to avoid that for as long as possible on the new ride.