The modded connector with the wires joined is done when converting to manual to bypass the inhibitor, easiest way to do the wiring if you can find one is the de loom from an a31 or c33.
Cefiro did come with hicas on some models.
/\ NA box definitely has a smaller different drive, NA manual R33 etc onwards have the electronic drive for the small box.
S14 & 15 SR 5 speed should work but will need a different gear.
Hard to say from the pics, it could be a mix of what they had lying around, late s2 does have plastic CAS, it hasn't got the neo ps pump.
As you say see if it's got the drain at the front of the head, might not matter depending what parts are needed