"February 2, 1732-3, Hannah Deane sister to Capt. James Leonard, late of Taunton deceased, gave to the subscriber the following account of her relations &c-- ... Her Father's brother's names were ... 2 William Leonard ... William & John never came out of England'
↑ Birth year estimated based on the fact that Thomas and Elizabeth had a son William who was baptized and buried in 1628, and it is assumed that this William was born after him. This puts the order of William and John at odds with the source (in order to fit all the births in), but since they stayed in England, Hannah Deane might not have been aware of which was older.
The alternate is that this William was born before the one who died in 1628 and the 1628 infant was given the same name knowing he was dying.