Interestingly there is a Bryant Newcomb listed in Quincy Massachusetts. Also William Mead, which seems to be a common name, specifically a William T Mead in Quincy 1831-1847.
I wonder how these surnames are connected to Mr. Fernald. Perhaps they were nephews or married to either him or his wife's relatives. Or perhaps they played some role in their upbringing, say if either of their parents died young or were divorced or remarried.
Now I wonder also if Bryant is also somehow connected to Lemuel Fernald's family who was also from NH and disconnected from the Fernald line. Of course the Boston area would have attracted many people and these families connections I suggest may only be coincidential. But they could be clues, They may have been close friends or church members or had no affiliation at all!! I plan to reactivate my ancestry subscription this spring. Then maybe I'll find more clues, til then.