First try with homemade studio set up
Not a bad start at all but I few nit picks. Your son is turned away from the main light so his face is under lit. With both subjects turned to the center you want to light more from the center. Try clamshell lighting with this pose.
You want overboard on warning up the WB. I can see the separation between the subject's hair but a hair light(s) would have improved the image.
I suggest you move your fill light so that it is right next to the camera lens on the opposite side of the lens from the main light. Using the fill light at an identical angle from the camera as the main light is not usually the best use of your fill light.
Here are some good references on lighting and posing.
Living and loving it in Bangkok, Thailand. Canon 7D - See the gear list for the rest.