HELP: Headlight switch triggering STARTER!!!

Assuming you had to lower the steering column to get the inst' cluster out. Your ignition switch has a built on wire harness that mates to the cars harness under the column. This white plastic connector has been known to melt and could cause the cross circuits you have.
Some of the aftermarkets replacement switches have a extra small gauge black wire where the the factory placed the orange wire for column shift indicator lamp. If someone plugged this in as received/connected that orange to the black, the fuse for illumination is blown soon as the switch is turned to on or accessory.