Presumably, you'd be including a lot of relevés in the class, piqués, and sustained balances, so I'd suggest maybe beginning with some floor stretches to massage and stretch out the backs of the legs, calf muscles, and limber up the lower back and to firm the stomach and overall trunk strength.
I'd also stretch out the sides of the hips some.
And in between sets of class exercises, encourage and even lead students through stretching out. Sometimes students don't know to do this, particularly if they're novices. Best wishes for happy teaching and dancing!