In May 2015 William had a close autosomal DNA match, Amanda. They were predicted to be third cousins which would mean their MCRA would not be too many generations back. But, Amanda was also searching for her bio family. She had recently found and made contact with her bio grandmother who shared that Amanda's bio grandfather had been born a Pierce, but had taken a new surname when he was adopted as a young boy. I always thought if Amanda could break through her brick wall, we would be able to solve the Pierce/Hallsted mystery for William.
In April 2016 Amanda contacted me after her research led to the names of her bio grandfather's parents. This Pierce line is very easy to trace online, and sure enough, we found a strong candidate for Theodore Hallsted's father in Gardner Pierce. Gardner is in the right place at the right time. He descends from Michael Pierce, as William's close Y-DNA matches do. With Gardner as the MCRA of William and Amanda, we can calculate that William and Amanda are 3rd cousins 2X--very much in line with the DNA evidence. Because of the circumstances of Theodore's birth (he was likely an out-of-wedlock birth), we may never have a paper trail to support the connection between Gardner Pierce and Theodore Hallsted. But the DNA evidence is strong enough that I feel we can say with confidence that Gardner Pierce is the father of Theodore Hallsted. This discovery breaks through a brick wall that Hallsted researchers have been trying to get through for a long time!