Logic says you can't prove a negative, so I can't promise you that they can't be obtained now. But the evidence suggests that right now, they are unobtainable.
First of all: there are three of them, you forgot to mention Badbara.
When these 3 dolls were implemented, there was also a new achievement related to the Bewitched event implemented. When asked about this, CipSoft said that it was done for a reason that would later become clear. To me it sounds like they were working on this specific event and, perhaps, another one as well. So these dolls could be either part of an extension of the Bewitched event or a completely new one.