I use different equipment than you, a 1DX and 400/2.8 but here's my input. On a 1DX focus case 1 works fine with track. If you are only focusing on one participant your rig should have no problem keeping them in focus.
I like the head on shots for hurdles. stand beyond the finish line at the curve so that you can be off the track and stay on your daughter. I really like the intensity of these shots since you are looking them square in the face. There are normally a couple of frames each hurdle that work at 12fps. The closer they get the better but you should be good from 1/2 or 2/3 into the race to the end with your zoom.
The other angle is from the side. There is some risk because it is more difficult to follow them moving sideways and the runners in the lanes closer to you could block a good shot of your daughter. From the side you get two or three hurdles to get your shot.
In both cases having the camera a little lower than standing height is good.
There are also creative things you can try with slow shutter speeds, zooming during the exposure, etc. Hurdles happen fast so use every race to practice, even if your daughter is not in it.