What an exciting opportunity!
A half hour is a very tight period of time but also very workable if you keep it simple. If it were me, I'd talk less, show more and get them dancing to something really simple so they recognize the freedom of Contra dance (no fancy steps, unlike the Ballroom dance). Agreed regarding the virtual dance compositions so far being tailored to existing dancers... so here's a couple that I'd feel comfortable using in your situation.
Be sure to test your tech for calling over music beforehand - many platforms fail to handle both without specific tricks.
Good luck - let us know how it goes!
Don
Easiest:
Haste to the Video Call - Solo/Singlet - Don Veino 20201116
No need to care about separate PNR roles. Obv. riff off Haste to the Wedding & for that tune.
A1 Line/2 Forward & Back;
(w/PNR) Sashay to Camera & Back (or repeat Fwd & Back)
A2 Allemande/Star Left to fill music; Right
B1 PNR Dosido 1x; Clap, 2-Hand Turn 1x
B2 PNR Dosido 1x; Clap, 2-Hand Turn 1x & face to camera
As solo, can omit any mention of Partner and face camera instead. Should be very robust, most moves can be reversed in direction with no negative outcome.
A Notch Higher:
Bubbly Starter - Solo/Singlet - Don Veino 20201116
No need to care about separate PNR roles. A1/B2 riff off my Sourdough Starter to make it easier.
A1 Line/2 Forward & Back;
PNR Dosido (or repeat Fwd & Back)
A2 Circle Left; Right
B1 Star/Allemande Right; Left
B2 Loop Single Right (away from PNR & back); PNR Swing
(can substitute Dosido for Swing if A1 done as 2x Line/2 Fwd & Back)
As solo, can omit any mention of Partner and face camera instead.