1. I don't think the year matters. The 93 MX6 (dunno about the MX3) had an extra coolant temp sensor that controlled the fans, (but you can always swap the neck from near the coolant filler cap if needed). The 93-94 MX6 had slightly different wiring to the distributor from the 95-97 (but you can swap the disty if needed).
2. I don't know. But those intermediate shafts are now unobtainium, so grab it just in case.
3. I don't know. But the KLZE has different VRIS points, if I remember correctly, so I would grab it just in case. It might run better.
4. I don't know.
This board is getting pretty quiet too, 626.com is even quieter, and ProbeTalk is dead, so stick around.