Name, year and country of birth from search on New Zealand BDM website in April 2019:
1911/16074. Young, Agnes Mary. Mother: Helen. Father: John

Full date of birth of 24 June 1911 from further searching in April 2019 on BDM Search by incrementally changing the date range for the birth. [Twin with sister Catherine].

There were two results for a “Agnes Mary Young in marriage search on New Zealand BDM website in April 2019:
1932/7443. Bride: Agnes Mary Young. Groom: Norman Ernest Johnston
1933/3498. Bride: Agnes Mary Young. Groom: Hector McFarlane Hollows

As at April 2019 - further research required.

Elder twin, name of husband as ‘Norman Johnston’, from Paul Young in a ‘draft document’ attached to an email dated 14 July 2020. Paul is the great-grandson of Albino Montizino (1848-1923).

Result of marriage search copied from above:
1932/7443. Bride: Agnes Mary Young. Groom: Norman Ernest Johnston

Full date of marriage of 29 June 1932 from further searching in July 2020 on BDM Search by incrementally changing the date range for the marriage.

Year and country of death, date of birth, from death search on New Zealand BDM website in July 2020:

Year and country of death, from death search on New Zealand BDM website in July 2020:
1993/45849. Johnston, Agnes Mary. Date of birth: 24 June 1911

Full date of death of 18 August 1993 from further searching in July 2020 on BDM Search by incrementally changing the date range for the death.