...and the best I could determine, from internet searching, is that most sources believe
Idony derived from Norse Idunn (don't know how to make the "d" into that special character). Idunn seems consistently to be stressed on the first syllable and, according to multiple sources including a male from Iceland on Forvo, it's an "ee" sound, not a long "i". Some sites also connect
Idony to
Idonea and, best I can tell, this begins with an "ee" or "ih" sound, but is stressed on the second syllable.
A general google search turned up some "tube" videos featuring individuals named
Idony. In
America, the second syllable was more often stressed and the "I" was pronounced as either "ee" or "ih". In Britain, all examples, ranging from toddler to teen, were stressed on the first syllable and the "I" was long, as in "ice".
It seems likeliest, to me, that "EE-do-nee" is most correct, but I love the sound of "IE-do-nee", so that's how I choose to say it. Very similar, in my mind, to the old British pronunciation my family used of "so-FIE-uh" rather than "so-FEE-uh".
Of course, I only made an internet search, did not consult any name/language experts or tomes, so take the above with a grain of salt.