I. can't be certain of 1 because mine (was) auto not manual cluster, but I don't have a main headlight (not high beam) dash light. The hint is that the dash backlights come on
2 and 3, these are fog lights. Position 1 on the switch gives you the front fog lights + parking lights including dash illumination. Position 2 turns on one rear red light as well as the dash light. As a result you only get 1 reversing light and will forever have kindly people stopping you to tell you one of your reversing lights is out.
4. Is for the front not rear screen, you have the "Winter options pack". That switch turns on the front windscreen wiper de-icer (element in the windscreen, if the windscreen has never been replaced). You should also have heated mirrors, a centre diff lock switch and the fog lights from q 2/3. There is a separate rear demister switch