My second grade teacher was a Miss Mildred Costain, arriving in Canada from the IOM onboard the SS Canada in June 1910. She was a passenger with her mother and siblings, along with my mother (Lillian Steven BELL), and her family. My mother and Miss Costain were great friends. Mildred passed away quite recently in Vancouver, BC, Canada (within the last 2-3 years).

Mildred had 2 sisters named Maggie and M.E. Their mother's name was Kathleen. See the following site for ship's passenger details:
http://www.immigrantships.net/ (Immigrant Ships Transcribers Guild) - click on Passenger Lists, click on Volume 3, click on year 1900s.

Might not be any connection, but worth considering.