The lever there is for your choke, should be attached to two cables that go into the engine bay and attach to your SU's.
The light is supposed to have a switch on the back of it to turn it on and off, thats the light in the engine bay that is loooks like yours has broken off...
Clock and voltmeters not working is a common problem and easiest fix would probably be to replace them, some of the hoarders on here probably have some working ones that they may be able to part with for the right incentive.
The two random wires on your firewall i have no idea from just looking at them, try to trace them back to their source.
Yes your car should be fitted with a passanger footrest, nifty little things if you ask me
Other then your few problems looks like you have picked yourself up a pretty clean car there, nice one mate and welcome to the joys of Z ownership
Smurf