It's alive! I've gotten everything assembled onto a cheap used bike. I've been using it for about 2-3 weeks now, for my daily ride to work, which is about 8km one-way. On the flat I hardly use the motor, maybe at the lowest level if I'm really lazy. But as soon as it goes a little uphill then it's fantastic, I'll be cycling with the highest gear pretty much all the time.
Needed some special tools to remove the freewheel from the old rear wheel and put it onto the new one with the motor, as well as a crank puller to install the PAS.
Used tie straps (some even came with the leafbike kit!) for cable routing and I found an old little bag lying around to stuff the controller into with all the cable slack. From my usage the controller only gets slightly lukewarm, I may think about moving it out of the bag to somewhere more ventilated in the future.
Only thing I haven't figured out is how to use the regen brake. There's a group of three buttons (cf attached pictures) which are yellow, green and red. The yellow is an indicator switch, like on a motorbike, the other two are just buttons. It doesn't seem any of them actually do anything though. Anyone know how the regen brake works on these kits? I'm going to send out a mail to leafbike otherwise.
EDIT: and the cylinder lock on the battery pack just came out today

luckily I didn't loose any of the small shims inside, only one of the small springs. Has anyone had this happen to them? I'm going to try using a screwdriver of some sorts to lift up the stopper so I can take the battery off the frame. I'm hoping I can then push the stopper up by hand from the outside of the battery and slide the cylinder back in and turn so it's back into its regular position
EDIT: fixed the cylinder lock! Went as expected, a screwdriver was enough to lift up the stopper and get it all back together. Still not sure how it came out though