Name, year and country of birth, from Birth search on New Zealand BDM website in June 2018:
1887/5142. McGregor, William Charles. Mother: Kate. Father: Charles

Year and country of marriage from Marriage search on New Zealand BDM website in June 2018:
1924/5993. Bride: Beryl Mavis Siddle. Groom: William Charles McGregor

New Zealand Electoral Roll - Auckland Central General Roll for 1911, found in June 2018:
McGregor, William Charles, 2 Canada Street. cabinetmaker
McGregor, Charles Grove, 2 Canada Street. carpenter [Father]
McGregor, Catherine Jane, 2 Canada Street. married [Mother]
McGregor, George, 2 Canada Street. settler [Brother]

New Zealand Electoral Roll - Auckland Central General Roll for 1914, found in June 2018:
McGregor, William Charles, 2 Canada Street, cabinetmaker
McGregor, Charles Grove, 2 Canada Street, carpenter [Father]
McGregor, Ethel, 2 Canada Street, spinster [Sister]

New Zealand Electoral Roll - Auckland Central General Roll for 1919, found in June 2018:
McGregor, William Charles, 2 Canada Street, cabinetmaker
McGregor, Charles Grove, 2 Canada Street, carpenter [Father]

New Zealand Electoral Roll - Eden Roll 1925, found in May 2025:
McGregor, William Charles, Troonville Ave., Mt. Albert, builder
McGregor, Beryl Mavis, 19 Troonville Avenue, married

New Zealand Electoral Roll - Eden Roll 1928, found in May 2025:
McGregor, William Charles, 19 Troonville Avenue, builder
McGregor, Beryl Mavis, 19 Troonville Avenue, married

New Zealand Electoral Roll - Roskill Roll 1931, found in May 2025:
McGregor, William Charles, 17 Duncan avenue, carpenter [Living with Brother. William's wife, Beryl, is living in Whangarei]?
McGregor, George, Duncan avenue, cabinetmaker [Brother]

Entry in the NZ World War I Army Reserve Rolls 1st Division 1916, found in May 2025:
McGregor, William Charles, Cabinetmaker, 2 Canada Street

Full date of birth of 18 July 1887 from further searching in May 2025 on BDM Search by incrementally changing the date range for the birth.

Full date of marriage of 29 October 1924 from further searching in May 2025 on BDM Search by incrementally changing the date range for the marriage.

Preferred name of “Bill” from Obituary of brother Henry McGregor found in May 2025:
https://paperspast.natlib.govt.nz/newspapers/AS19450813.2.2.4
McGREGOR. - On August 11, 1945, Harry, dearly beloved brother of Grace, Janet, Ella. Topple, George, Bill, Fred, passed peacefully away.

Divorce Notice from the Auckland Star of 25 May 1933 found on the Papers Past website in May 2025:
A decree nisi was granted the petitioner on the grounds of a deed or agreement of separation in the following cases:-
Beryl Mavis McGregor (Mr. Moody) against William Charles McGregor;…

No record of death for William could be found on the New Zealand BDM website as at May 2025.

No record of burial in Auckland for William could be found on the Auckland Council Cemetery Search website as at May 2025.