Not quite sure I see why there are the various ponytail lengths when there are already hair length tags independent of style. Regardless though, if ponytail is a specific positioning independent of other positions (such as side ponytail) then you shouldn't tie length to any one specific position, so -1 to short and long.
As for high ponytail, that depends on how ponytail is defined. Is it all tails in the back or is it a specific level? Are low and high ponytails considered unique positions from regular ponytails? If so, then you can't implicate high ponytail to ponytail either.