As you can see from the picture below of a B744 cockpit (ext. lights section), there are separate controls for landing lights: inboard and outboard. Hope that answers your first question.
I'm not sure about the brightness thingy, but I don't think the pilots have control over that.
The landing lights are turned on after receiving takeoff clearance and are turned off after 10,000 feet. They are turned on again after passing 10,000 ft during descent and turned off after leaving the runway.
I hope I helped!