I'm reluctant to impose any recommendation, as "Sister" suggests to me that she she could be a nun. A simple papist may well be deluded or deceived (but not necessarily in that order) but nuns are more glutinously committed. They study enough to know what God desires, I'd have thought, but then do something else.
click on either graphic for more detail if required (such as of footwear or the egshell tiara)
Which of the depicted styles more closely resembles your Irish friends? You didn't say they were both Irish but they presumably are. Perhaps then I'd be better able to suggest something.