Those must be my pics then... :-)
2 weeks marocco tour during christmas/newyear a few weeks ago. Did this tour: Ceuta, Chefchaouen, Fez, Midelt, Merzouga (erg chebbi), piste direction Zagora but had to backtrack because of mud, Tinerhir, Gorge du Todra, Imilchil, Meknes, Chefchaouen
Foum Zguid - M'hamid: I did it in a 4WD a few years ago. Never did it in the 2cv though. From what I remember from the piste it should be possible but you will get a hammering and probably struggle a bit in the sandy parts. Consider fitting a bashplate under the engine/sump/gearbox
2WD and pistes... always think twice ofcourse and seek local advice...