I discovered that the Charles Gibson connection is through the Howard family. Mary Ann Howard daughter of Marcellus Howard and Sarah Hodge m. Charles Gibson. Their family is the one in Chatham, Kent that John visited. Charles Marcellus Gibson and his wife Clara son of Charles and Mary Ann. And Jon also visited Samuel Hill and his wife Jane Adelaide Gibson daughter of Charles and Mary Ann.
Still wonder about the Hadlow connection. However, the Gibsons in the daybook seem to be Howard, not Hodge connections.