GTI6 swapped Partner - sensor question

[Partnermike]

Heres one for you tech-heads. 

Car is a 2002 Partner Combi. We have swapped the 1.4 for a 306 gti6 engine but I could do with some help. 

We have used both ECUs - only using 4 wires really from gti6 loom (12v constant, 12v switched, fuel pump & ground). So all BSI (central locking, lights signals etc) are still working.

HOWEVER...

ISSUE 01 - when I use the two coolant sensors from the Partner engine in the 306 engine thermostat housing - plugged in to the Partner ECU (assuming one is signal to clocks and one is signal to ecu) I get nothing on the dash in regards to water temp. My understanding is they are NTC sensors so one wire is voltage supply, the other is is feed back once the resistance drops. And I assumed they earthed through the block perhaps? So the only coolant sensor from the 306 is the ecu one (green) which still goes to the gti6 ecu. Seems like it should be very straightforward. As far at as the Partner ECU knows, its getting the same reading it was before?

ISSUE 2 - I noticed the Partner speedometer sensor was virtually identical to the gti6 one (same plug etc) so I just changed the top hat of the sensor (just incase the chip was different) and plugged the Partner ecu directly in to it - but again nothing on dash. Its been suggested to me that the VSS may only get power whilst it has tach signal, so no RPM no VSS?

ISSUE 3 - this one is more technical and WAY out of my paygrade. Splitting the crank sensor signal. Obviously the gti6 ecu still needs crank signal but Id love for the standard Partner dash tach to work. We have split the signal but will this weaken the pulse? So at the minute the gti6 ecu is plugged in and so does the Partner ECU, engine runs but again getting nothing on the dash.  

I hate CAN Bus - its far too clever for me, I want 1 wire to 1 wire function. Is there anything obvious jumping out to anyone on here that would help? As far as Im aware there is a good earth for the Partner ECU so assuming that earths the plugs? Do other plugs need plugged in to close a circuit for power supply with BSI? Im lost.

Thanks for any help!

[Partnermike]

Ok small update, got the VSS working last night, just ran 12v straight to the sensor and used a drill to turn the sensor out of car. Dashed picked up signal fine. So it must not being getting power sent through to it with the tach not working, or maybe somehow Partner side of the loom isnt getting power at all? Unsure how to test if the ECU is putting out power to plugs that needs 12v/5v supply.