I'm sorry for your loss and all the tsuris you've gone through as a result.
I went through the responses to see if there was an update. I’m surprised there isn’t one. I’m surprised people aren’t still reading this (as I just have... because...ta da...it just popped up in my feed! as you will...) and that you aren’t answering notes with news. Did you ever contact those cousins? Was it because you didn’t invite them to the wedding; that you weren’t talking to them as much as you were to your aunt...things like that which can build resentment and estrangement of a sort over the years, especially when you live at a distance (just thinking out loud as someone who has been, shall we say, in those shark waters...). Or have you chalked it up? Better a mystery than something you’d rather not know? Or maybe something truly unknowable. Some things really are unfathomable after all.