Yes, RGB lights can be turned off at any time with the remote control to help you save battery.
Yes, the RGB lights can stay on 1 color. Use the sync button ( Top right ) on your remote control. After your led lights are in sync with the music, then push the color button on the remote and you can pick a solid color of your choice.
The soundbar mounting hardware is designed for a 1.75 - 2.25 inches roll cage, you'd have to measure the diameter of the bar to fit the unit on.
Cigarette lighter 79 inches; USB input 18 inches; AUX input 9.4 inches; 12V DC converter 40 inches.