I dont' know why I was thinking I needed to be around 1/1000 to freeze roller skating. I guess I was doing some math in my head that a person on roller skates would be traveling faster than little kids running on the football field.
Don't forget in this situation, where you have a low ambient light level and you are using flash, it is the pulse of the flash that effectively becomes your shutter speed. Think of this situation, in a totally dark room with a flash light, open the shutter with B, so it just stays open, as there is no light the shutter time becomes ineffective, it is how long you turn the flashlight on for that determines your exposure. Same thing is happening once you are killing your ambient exposure at the roller rink. In HSS, anything over 1/200, your flash will pulse for the entire exposure, it doesn't send out one burst but many little ones, once you go below 1/200 you just get the one burst and so your subject shutter speed becomes the flashes pulse duration.
To gauge exposure, meter the scene without the flash on, say it is 1/50 @ f2.8 and iso 400, once you go two or three stops under that the ambient becomes less and less effective. Set your camera to 1/200 @f2.8 and iso 400 and the flash will become the effective shutter speed for the subject, the ambient will fall a little less than two stops under exposed though the flash will bring it up, but you will have zero noise and much more dynamic range, you will also put your daughter into some context as the background will be visible but not distracting.
You don't need to buy anything for shooting where you did, the Rouge is great and I have the larger version, but with 10' ceilings you don't need it.