Irene pronounced with three syllables - better still, Eirene pronounced with three syllables - is beautiful and classic and stylish and lyrical and doomed. And Irene pronounced iREEN is dreadful and inevitable.
But if you use it as a mn and know in your secret heart that it's got three syllables, wouldn't you win twice?
As for your pattern-making granny, I taught a Rina once who should according to her family tradition have been Irina, but they bowed to the inevitable I suppose. So that might cheer her up!