Ah, and I'm here to point out an error on your part that may not make you happy
, but will hopefully help you with future attempts.
You didn't fail your first attempt. In cases of multiple birth (twins/triplets), you may
choose your heir. It's the one who's a different life state in the first
birth - it's NOT the first
born.
So you choosing your 2nd born as heir was perfectly legal.
In fact, with those three, you had your choice of who to be heir - either human
or the genie ghost.