Okay well I would start to have them do cast, drop, two back hip circles in a tight hollow (but not "hip" circles, actually trying to stay lower down on the legs). To see if they can get and keep momentum.
Then they can try to do two clear hips in a row on strap bar. Wherever they open to in the clear support. This should work up to three. They might need some spot.
For the drop back if you have a soft mat you can set up a drop back drill. Lower the bar down so they can just cast without hitting over a soft, resi mat (or like the L4 vault system) and then they do cast, drop to their back under the bar in a tight hollow. Make sure to maintain the tight hollow.