Yes, I've read all that material too, but after reading the life of Sir William and especially this Pippinger's work, I am inclined to go along with him. We know that Sir William married about 1601 and John was 4th son. I would not think that he would venture to America so late in life and then marry and start a family. Pippinger evidently does not think so either. He supposedly died soon after being released from debtor's prison---I believe about 1641. I don't have the material in front of me, but he quotes some source of reference. You might like to get this book from interlibrary loan. It is very interesting.
Helen Smith