Super Moderator//Exceptional Service Award Recipient
You have two beautiful girls there.
Ms Purple head is a sky blue recessive pied.
Your other foster is a cobalt violet, yellow face type II dominant pied opaline budgie.
As for their age, I'd say they are both at the very least 6 - 7 months old. You can get more accurate info on their real age by checking their leg bands.
The bands would usually have numbers and letters, but the year
the bird was hatched would be the last 2 digits of that year
i.e. 2016 would be 16 (stamped cross-wise on the band).
If you've had them not quite a year their band should have (16)
printed, when they were hatched. They're beauties.