Memory might be expandable... it depends on your control. It was available then. If you have an M1 or M2, you'll have to contact Mazak. Might not have much luck there though do to the age of the machine. It might be possible from the board manufacturer (which again, depending on the time frame) could be either Mitsubishi or Yasnac.
DNC is possible only if you have the DNC option for the controller. If you do, you can use DNC software to run the large programs. If not, again, check with the board maker.