Drawers can end anywhere from just under the knee, to just shy of the dress hem (mid-calf-ish); it's really variable, so anywhere you're comfortable with, you're likely fine.
Hems on most children's things are a simple turned hem, no facing; some dresses do have facings, so again, there's variation. I find the turned hems seem to be predominant, though. Just turn a smidge under, then turn under 2-4" to form the hem, and running-stitch it into place. No need for a fancier hem stitch.
That's a really good price on jazz shoes! Unfortunately, jazz shoes lack enough sole to be safe for a running toddler. They're very thin, to allow the dancer to feel the floor when moving. May I suggest hitting thrift shops or other low-cost avenues for ankle-high leather boots? Any area with horse riders will tend to have used "ropers" or "paddock boots", that can work really well, and sometimes, at this time of year, you can even find plain "leather look" ankle boots (no padding in the ankle area) during "back to school" type sales. My kids prefer real leather, as it's cooler, but some of the very matte man-mades are unobtrusive.