Great list. You forgot Crossover slope:
The crossover slope describes how sharply or quickly the crossover attenuates (decreases) the amplitude (strength) of audio signals at frequencies above (low pass crossovers) or below (high pass crossovers) the crossover frequency. The slope is described in dB per octave. The higher the value, the sharper the roll-off, and the more control the listener will have over which frequencies are played by any particular speaker. A 24dB/octave slope is considered very steep (good) and a 6dB/octave slope is relative low (more difficult to control audio signals).
