Does removing an LED bulbs from fixture decrease energy usage?
Yes, that will cut energy use in half, though the type of bulb (LED, CFL, incandescent, one that's not invented yet) does not matter.

Of course, you also get half the light.

A bulb which is removed does not use any electricity whether or not the fixture is switched on (James Thurber's Grandmother notwithstanding, for the literarily inclined.)