It's WHY Daniel had to die first...and only 3 days after Dannielynn was born.
THe plot probably was conceived just before they went to the Bahamas...shortly after Larry signed off on the "sperm donor" agreement. (Which remains hidden and probably destroyed.)
It's a secret that Larry will have to carry to his grave....
But finding it would open the door for Virgie and Anna's father and Anna's ex as primary heirs.
You're on the right track, IMHO. The Bahamas, as DL's birthplace, was planned in advance. Wouldn't you love to see Howard's computer hard drive?
In a way, this secrecy reminds me of the Elizabeth Smart case. We NEVER heard the 911 call that Ed made, as we often do in other cases. In fact, the police chief Dense said there was an error on the log - mind you, police logs are now computerized and have been for years.