for the sixth, change your name "Anna's child".choose all the options adding Zu-points(avoid losing it as well). pick "call Marci(or Tiller)" and "get the code from the seller"then you can get ending6
for the eighth,after the option "help Anna's children to get the code",when you meet the second android,pick "i guess we'll trade".this leads to ending8
for the twelfth,you just need to pick all options that add MC-points(avoid losing)and follow the guide(the"after calling Tiller/Marci"one),then you can get ending12
the above is how i get these endings.hope this helps!