These are great shots. Some ways to improve:
1. Crop tighter and pay attention to things around the edges of the photo.
In #1, get rid of ref's hand and leg.
In #2, you chopped off feet in the photo, so maybe crop off all the legs. Also watch those chairs in the background: try to crop between chairs, doors, people.
#3, remove teammate ... it's very distracting to see a sliced bit of body nd the odd bit of shoe.
#4. What's that dark bit on the wall on the right edge. A good crop would remove it.
Also think about what many folks have posted many, many times before: face, ball, action. It's OK to have a photo without the ball, but after the third game, your #1 and #2 photos are gonna be boring. They could've been taken at any game or practice in the season.
If you want more light (always useful), you are talking about a slave speedlite. Remote triggering has been discussed lots as well. You did not state if the flash was in manual mode or ETTL mode. I'd go with manual mode. Try output 1/2 or 1/1 for starters.
If you want more help with youth basketball see www.coachesclipboard.net
which will get your daughter off on the right foot with respect to ball handling, shooting form, BB techniques, etc. It won't help her tuck her shirt in though. 