The bio mentions a brother of Gad's named David. That David James would have had Elizabeth and William James for parents, even though he'd be referring to a Elizabeth (Phillips) James who died back in Wales. She's still his mother. He was born when she was seventeen, which is possible. I think the David James in the Utica cemetery might be one of the siblings you were thinking might have emigrated ahead of the family. It makes sense that you'd travel to a place where someone you know is already established. For this David to be Gad's brother, he'd have to be the oldest son, which is just who you'd send off to scout ahead for the family. This explains the thing that is mentioned in passing in Gad's bios about him going first to Utica, NY. I didn't give that much thought, but he probably went there because there was already family there. This is brilliant.

And yeah, I always thought the whole family changing their name seemed suspect, but ...