[Radek]

Mummies in the coffin area. YES, all mumies can drop all anks. YES, if you are patient enough then you can get a particular ankh from any mummy by killing it repeatedly. Sometimes, you have to be really patient.
Note: You can wait for an ankh at a mummy in a coffin but not at mummies "at large", which will appear later in the game. Possible reason:
1. The loot is created when the mummy is created.
2. If the mummy is in the coffin then the mummy is created when you open the coffin.
3. If you spot a mummy at large then the mummy is "already here" so that it is too late for saving the game and trying to get an ankh.