The highlights:
3.5" BW Screen (composite, 5V modded)
3000mAH Galaxy S2 battery
Pi Zero non W (was building with a W but it died during assembly)
I2S Audio with volume control in original location
Common ground PCB to GPIO for input
Auto low power shutdown (with on screen low battery warning)
On, charging and charged status lights
Contrast slot for mSD card access
Full sized USB port in Ext spot
DC charging socket in original spot.
The goal for the build was to use minimal hot glue (or at least visible and other than a little for some wire management I think that was achieved).
To have as few a wires as possible between the two halves, there are just 3, 2 for power and one for the auto shutdown/battery warning.
And to keep the outside looking as stock as possible.
Pics - if I ever do another one I will likely modify some of the GPIO pins used for the controls to tidy up the wiring a little bit.