I feel that there could well be a connection here. It is too much of a coincidence that your father, grandfather and great granfather had the same three christian names, and in the same order as my uncle, plus they all apear to have come from Bucksburn.
My mothers family name is Dyce and are from Inverurie. I have visited both these areas of Aberdeen both as a family member to relatoves, but more recently on family research. They are situated about 5 miles apart and both are little more than large villages today, not really big enough to call towns. Although Aberdeen has grown in size and taken up the open spaces that were between it and Bucksburn. Inverurie is still in a ural setting. One hundred to two hundred years ago they both would indeed be far smaller than today.
My mothers eldest sister Isabella Saddler Dyce married Alexander Gray Hendy Milne. But as I said earlier, this man was also her cousin and also a cousin to my mother and her other siblings. But I do not know in what connection.
When one considers that scottish tradition is to give a second christian name to a child, generally the name of the mothers family, or even granmothers family for a second or third child as with my mother Nellie Smith Dyce. Smith was her mothers surname.
I feel that the names of Gray, Hendry, Milne and Dyce are connected.
Stuart