Paul,
the hazard switch knob unscrews on my car. In fact, it unscrewed by itself and fell off! I haven't removed the switch but would guess there is a nut under the knob.
The ignition lock has a clamp bolt on the tube that joins the lock to the steering column. The bolt must first be removed. After that, there is a button on the tube that must be pushed in, and then the ignition lock can be rotated and pulled out from the steering column. The button may be a little hard to find, a good cleaning in that area helps.
I don't know about the light switch, sorry.
George Davis
'69 280 SL Euro manual