Engines running without a catalytic converter will have an odor which is now evidently considered unusual. We all used to be accustomed to it, and thought the sulfur aroma from cars with cats was unusual when it first appeared. Now we are all desensitized to the cat aroma and notice the plain gasoline exhaust as "strange." If you hang out at race tracks or small (general aviation) airports you might not think the straight exhaust odor is strange at all. Adding a converter without adding an air injection pump could be a problem.
Headlights flickering at idle RPM can mean an adjustment of the voltage regulator is needed. It is a simple voltage check and gap/spring adjustment of the field relay.
The carb has a fast idle cam which actuates with the choke. If it is idling high when cold, the choke is also applied to some extent. Most 2CGs and 4MVs have a choke pull-off adjustment to ensure the choke is at least partially open once the engine is running.
Changing the plugs, wires, points, condenser, cap, and rotor can't hurt anything as routine maintenance, but it is unlikely to solve the the behavior you describe.