I can't see your photos now, so no cooments there. I would like to make a suggestion though. While you are in the flash testing phase, use an inanimate object and a tripod. Do this while you are alone and not likely to be distracted.... kids are asleep.
You might as well start with TTL. Go through every conceivable setup you can think of for both camera and flash. Take notes. Don't expect miraculous images. Notice the light patterns and light intensity.
Now do the same thing with Manual flash.
Be patient, this could take longer than you would want, but the payoff will be worth it.