Jeakins a diminutive of Jak, which is probably James, French Jacques, though it might be a double diminutive of John (-> Jak -> Jakin -> Jeakins). The Ny- beginning gives Nyswonger a Swedish look, but there is no W in Swedish. Maybe an altered spelling of a Swedish name, or maybe not Swedish at all. A convoluted way of saying I haven't a clue. Sivard too could be Swedish. It is a Swedish forename, the same as Siward, Sigurd , Sieghart in other languages. But then why not Sivardsson, the patronymic form favoured by Swedes? That's another "don't know".