Some good experimental shots with the Rogue One. One essential to keep in mind is this: Working in a confined space like a bathtub or shower location causes the source of the light to, in general, be very close to the subject. The closer the light source is to the subject, the more-rapidly the light falls off in intensity. This light behavior is regulated ed by a principle known as the Inverse Square Law. What the Inv. Sq. Law means in practice is that you'll get very "hot" highlights, and very deep, dark shadows when the light source is close to the subject, and as the light-to-subject distance increases, the rate of fall-off over distance becomes slower and slower and slower; by the 20 foot mark, the light will have almost no measurable falloff in intensity across say, a 10-foot wide picture area.
The bottom photo, the second B&W image, shows the Inverse Square Law at work, with very dramatic light falloff, in lighting that makes a real B&W impact type shot. I think you did very well on these in show the child's facial shape and structure. Hand-holding the flash is a time-proven technique to get varied lighting, fast, in situations like this. Good job on that.
I think you did alright with these shots!
One thing I have learned about bath/shower/boat cabin type shots is that exactly where the flash is placed can be very important, due to the small size of the space, and the short flash-to-subject distances normally involved. At times, bouncing the flash off of one surface is bad, but another surface is good, and maybe (maybe!) a third surface will be great, depending on the desired type of "look" to the flash lighting.
