|"I noticed your boys are on a skateboard and inlines. Is this because they arent big enough for quads with wide trucks or was it their choice?"
It is their choise, and it's also easier to find cheap/lite inlines that you can adjust in length to their growing feet.
But my oldest son still prefer quads for long distances (he's 13 years old and have now is own quads. I must confess he learned at 3 with fisherprice/worn kryptonics)
"Just because right now I'm wondering if the narrow ramp trucks wouldnt be wide enough to do some of the tricks. "
Lisa narrow 3" trucks should be fine for you, with about 60mm wheels. Using centered cores( or not centered) wheels (and wide or not) enables you to tune the final real width of your setup.