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When lighting multiple faces in a group shot (2 or more) it is very difficult to get flattering natural looking light on both faces when they are facing opposite directions.
With the pose as is you'd want to use two gridded or snooted key lights. One you would want to place behind the mother 45° from her nose (135° from camera axis) and 45° above the eye line, to "short" light her face with the broad side in shadow. Then for the baby you'd want to place it's key light similarly — RELATIVE TO THE NOSE and EYES — 45° to the left of the nose (about 90° from the camera axis). That creates a crossed lighting scenario which will wind up not putting much light at all in some places neither light reaches. To prevent those dark crossed shadows in this and any other lighting pattern put a fill source about chin level with the subject with your camera directly above it. I use a 22" dish with a sock for my fill that way most of the time.
If you changed the pose and had mom looking full face at the camera and not hidden by the baby it would be much easier to light. With mom looking full face the and the baby angled as it is you'd be able to get both faces in the key light placed to the left 45° from mom's nose, with fill again kept near the camera. The light behind at 135° from the camera axis would become rim lighting on their backs.
Lighting the face of a reclining person isn't any different than if upright because perceptually the viewer will look for the same highlight/shadow clues to 3D shape on the face. So in terms of key light placement on the baby's face there are two options that will produce flattering, natural lighting on the face:
Butterfly: In a butterfly pattern you aim the nose at the key light and angle it 45° downward to the eyes. For example in shot #2 if the key light was to the left and forward, level with and aimed at the spot between the baby's eyes the face would have a butterfly pattern on it similar to what you would see if the baby was held the same way next to a window to the left.
Short lighting: Placing a key light 45° to the side OF THE NOSE and 45° above the EYE LINE will, due to the shape of human faces, create a "mask" pattern of highlights on the forehead, top of cheeks, and top of chin that naturally define the 3D shape of the face.
Those patterns seem natural because those are the angles natural light comes from at 10AM, 12 Noon, and 2PM:
Morning: "short" pattern complements "oblique" facial angle
Noon: "butterfly" pattern complements symmetry of full face pose.
Afternoon: "short" pattern complements "oblique" facial angle
So if you keep your key light oriented at 0°H45°V to spot between the eyes (butterfly) in a full face pose, or 45°H45°V to spot between the eyes (short) in an oblique facial angle, regardless of how the face oriented (upright or laying down) the face will wind up seeming more natural looking and flattering in the portrait because those patterns match our mental image of what a face should look like. Short lighting a reclining figure is difficult without a boom to suspend the light in mid air to keep the stand out of the shot.
What you want to avoid — if you want natural looking lighting — is putting the key light at eye level or below which as the effect of reversing all the natural modeling clues, giving faces a sinister, otherworldly (lit from the fires of Hell metaphorically) appearance. The same cause and effect as making a scary face by holding a flashlight under your chin.
In terms of posing faces in reclining poses are easier to relate to at a 45° angle than horizontal. That's the reason the second shot with the baby at an angle looks less static and is easier to relate to than in 3 and 4 when held horizontal.
So to put this all together, try this next time:
1) Angle the baby upward 45° not horizontal - take off the watch.
2) Place the light for either butterfly or short lighting on the baby's face - try both.
For the group shots:
Start with poses where mom and baby are looking at the camera full face with centered butterfly lighting.
Next have mom look full face and baby to the left, with key light to left short lighting mom's face (45°H45°V) from her nose. Then coach her to move the baby to get it in flattering light also at the same time.
When shooting stop and look at the edges of the frame. Crop wide enough at capture so you don't chop off limbs. You can refine the crop / composition in the editing stage.
Don't make the clothing and background so dark it becomes a cave. Fill at chin level just under the lens of the camera will allow you to control the detail. Better to overfill a bit at capture and burn in during editing than to wind up with a "vagrant" baby and Daddy — i.e. no visible means of support.
When setting up lights I put a black and white towels on a stand and adjust fill until I can see detail in the folds of the black one, and then raise accent and key so accent is just below clipping (retaining detail in the white towel) with the key intensity in front slightly lower by eye until the balance of accent / key in the playback looks natural.