Mk1 9a 16v wiring

Couple of wiring related queries when putting a 9a (KE-Motronic) engine in a non gti mk1:

I've sourced an in tank lift pump that has 3 pin connector, I've got 2 carb wires, purple/black and brown,what 3rd wire do I need? (I've also fitted an external pump)

9a engine doesn't have an overrun cut off valve, airbox is also blanked off where it should connect to, I've read that the 9a ecu manages this however I'm using a KR ecu in the golf, do I need to source a valve and wire it in or can I run without one? (I've sourced an idle control unit to manage isv etc.)

Throttle valve switch has 3 wires, black/yellow, black and white. I know black/yellow connects to ecu and idle control unit. I assume black is ignition live? What / where does the white wire connect to?

Fuel metering distributor on the airbox has 2 plugs, a 3 pin on the left and 2 pin on the right. I think the 3 pin is the potentiometer and front r/h 2 pin is the WUR, is this right? If so do I need to wire in the potentiometer?
Also am I right in thinking the WUR has a wire from pin e/14 on the fuse box and the other is an earth?

Any help with any of the above would be awesome!