If you’re planning on shooting a little one outside or inside a soft light is always the best. I find it best to use a 2 x 2 soft-box and the smaller the better. The smaller the modifier on artificial light the more of the little one is being lit evenly and not over powered. I have kept with a one light set-up for children. A small umbrella and even a beauty dish could give a softer more even light. If I use a beauty dish I use the white sock that acts like a soft-box over it and make sure the power is low. If there is more than one person in the photograph then I would use the same modifier on another light and might switch it up to a larger umbrella or soft-box. When photographing babies I also like to keep a low aperture which also helps with the soft effect.
These are a few photographs of Gabriel from last fall. I used a low depth of field on these, and a 2 x2 soft-box.