Keep in mind that continuous lighting does not really put off as much light as it looks like it does. This will cause you to have to bump the ISO up higher then you think you will need to or open the aperture wider then you think you will need. But you have the camera and lenses for it.
With two or more people, i try to stay at least at 35mm or more to minimize distortion. If you can zoom in and get further back, avoiding getting the lights in the shot this can help improve your photos.
Any of your lenses should work for a portrait shoot. If you are like the rest of us and get a little nervous during a shoot, avoid even having your 16-35mm lens on or you will end up shooting wider then you planned.
Take your time, slow down, think about the shots, don't be in a rush. Yes i said it multiple times and ways, because this is your biggest enemy. You get nervous and end up just getting the shot how ever it may turn out. It is better to have a few great images then a lot of okay images.
Shutter speed. If you shoot at 1/250s with fairly still people you will be in good shape. If they are goofing around, 1/500s will freeze the action. You can get away with a slower shutter most of the time, but until you are really comfortable, keeping the shutter speed up will help ensure that you don't have motion blur. I would recommend getting radio triggers and start using the off camera flash in the near future. OCF Off camera flash will allow you to freeze motion at a lower shutter speed as well as keep a lower ISO.
At these shutter speeds, you shouldn't need a tripod.
Aperture. If you have people heads on about the same plane (distance from the lens, with multiple people) You should be fairly safe at F/4.5. If the group is up to two people deep F/5.6 is a safe minimum. If you just want all around aperture where you won't miss any shots, you can go with F/8, but this will require a high ISO. As you get more comfortable with portraiture, you can shoot a lot shallower depth of field (DOF). A wide aperture can take a portrait from a snapshot to a great portrait.
Try to shoot at about the same level as your kid. Avoid standing and pointing the camera down, unless you are doing an intentional shot from very high with a shallow DOF.
Avoid cutting off fingers or right at joints in the images.
For a great book on posing, look into Roberto Valenzuela's "Picture perfect posing" and PP practice. Lindsay Adler also has some great info out there. You can also get their videos from Creativelive.com
Welcome to POTN. Let us know how your shoot turns out.