I'm sorry but I don't see any of those surnames in this volume. There are 2 volumes available and I have the 1st. Additional copies of this book and the other can be purchased from the Hanover Historical Society.:http://www.hanoverhistory.org/
I do find, however, three Wm Richardsons in a book I own called ...... Hanover County, VA Chancery Wills & Notes. If this is something you still need on him, I can transcribe or photocopy this for you. Let me know.
In yet another book, I find no Cobbett but I do find Richardson & Wade...in the same paragraph.:
"Other places around Cold Harbor, which, in most cases, are still owned by descendants who have built new homes or remodeled the old ones are: McGhees, Stewarts, Boshers, Boze, Woods, Martins, Williams, Burnetts, Wickers, Adams, Gauldings, Richardsons, Mathews, Fords, Allens, Wades, Woodys, Grubbs, and others."
From a book called.... Hanover County, Virginia A Retrospective
Hope this helps! Good Luck.