Some information that hopefully may make your search a bit easier.
Newcastle and Chatham and surrounding area amalgamated several years ago into the city of Miramichi. Newcastle is on one side of the river and Chatham on the other. Miramichi cemetery is on the Newcastle side of the river. There are 3 libraries in the area so do a search for the one in Newcastle.
I came up with much the same info as aghadowey. I can't seem to connect the 2 sets of family members. I am starting to think this family may be more blended that just a second marriage between James and Laura. Perhaps 2 children are from that union and the children mentioned in the write up are children of Laura and not James at all. James (the father) died several years before his son James Willard and perhaps there was no contact or little contact between the first 3 sons that were born to James and Maud and the second set of siblings. James and Maud first child was born in 1897 and James Willard was born in 1922.
At the Provincial Archives of NB, you will find the death in 1920 of Maud MacDonald and it states that she is buried in Miramichi cemetery. The archives also have the delayed birth registrations for Walter James in 1897, Wesley Edan in 1898, 2nd marriage of Walter James in 1942 to Mary Georgina Duguay and marriage of Bernard in 1922 to Annie Edmonds.
http://automatedgenealogy.comhas the family under McDonald for both 1901 and 1911 in New Brunswick/Newcastle
A site that may be helpful in the Miramichi is
New Brunswick Genealogical Society, Miramichi Branch
www.nbgsmiramichi.orgThe death of James Willard states that he was a stewart on HMCS Warrier.
The home port of that ship would have been Halifax, Nova Scotia and James Willard MacDonald is remembered on Panel 6 at the Halifax Memorial.
There are a few museums in the Halifax area that may be able to put you in the right direction.
Shearwater AviationMuseum
www.shearwateraviationmuseum.ns.caHalifax library
www.halifaxpubliclibraries.cawww.halifax.ca/archives/index.htmlwww.canada411.cadoes have one listing for a Corbett on North Black River Rd, Miramichi
I would contact the public libraries and ask for a newspaper look up for the time frame of James Willards death as I am sure there will be a write up of some type in a newspaper in either Halifax or Newcastle/Chatham