Starderby

Oil temp sensor is not connected to the ecu.

The manual is correct, Aux 1 goes to 106 & 113, it is used for the fuel pump controller in GTR's and VTC in RB25 models.  No cars have both devices hence the same aux can be used.
Aux 5 is not connected.  
You have Ign 7 & 8 and Aux 11 on the expansion loom you can use, or possibly aux 2 is free on the main header - GTS dont normally have fuel pump speed control.  

If you wire whichever bulb you want to use to a spare aux output on the ecu then you can control it.  None of them are connected to the ecu in stock form.  

yep that would work.

correct.  And in the DI settings, turn on the pull-up.

typically I would expect the DI in the middle. It might be easier though to just have the DI and a ground and to turn the pullup in the DI on

That grey wire on pin 36 probably is in the engine bay somewhere not connected to anything.  But it wont be easy to find, it will be hidden under the covering.  It will be easier to depin it and swap to your AFM wire.

grounds for these should be on the sensor ground pin on the ecu. not on the chassis.
The Zada Tech oiltemp doesn't have outputs. its only a display
 

you probably already have an intake air temp. sensor (or a charge temp. sensor).  If possible, turn the ignition on with the G4+ connected to pc-link, and have a look at the runtime values (F12) , see if An Temp2 is connected or if it is erroring.
You will need to cut the wire on pin 29 (which was narrowband o2), and connect that to the AEM wideband wire.
If you look at the diagram I posted above (Nissan diagram) , you will see there are multiple grounds all connected.  They are all internally connected inside the Link ECU so it doesn't really matter which one you use (although I would be inclined to use a sensor ground wire like pin 50 rather than a power ground wire)
 

Can wire that wire into a digital input on the ecu.
Then could configure the ecu to change boost, timing, and fuel values when that is active.