I have ancestors with the name of William Jeffray in fact my great and great great Grandfathers were both named that.
The oldest William that I am familiar with was born in York County near Toronto Ontario near the village of Nobleton about 1804.
The spelling if Jeffray is unique but I am afraid the records that early in Canada are none existant to my knowlege but I am always looking. Family folklore says that an earlier generation came to the United States on a man o war as a tax collector in the colonies.
I don't know if this is of any use to you but you never know what could turn up.
Thank you for any consideration that you give this matter.