I think the "dock" itself could be USB C easily, it would probably also significantly reduce the cost of the dock.

> Adding the port, the USB-C PD circuitry may take up too much room.

You don't need PD circuitry for this. 5V 500mA over USB2 is more than enough. But the actual port and battery charging circuit is a bit ridiculous at this size.

I'm not sure precisely what the EU rules are, but the requirement should really depend on the dimensions/power of the device.