OTL slavery was not profitable in Canada's climate. Some French Canadian elites imported a handful of "house slaves" to flaunt their wealth .... and United Empire Loyalists brought a few slaves north with them, but quickly learned that it was frightfully expensive to feed idle slaves during Canada's long winters.
WI?
As for natives (Beotuck, Migmaw, Abenaki, Huron, Sioux, Inuit, Cree, Haida, etc.) Trudeau offered them seats in Parliament during the 1960s .... to dilute Québécois claims of "two founding nations"?
WI Sikhs or Chinese gained significant political power on the West Coast?
WI Chinese-Canadians provided labour battalions during WW1?
WI Sikhs enlisted in large enough numbers to form fighting battalions?
Would Chinese and Sikhs be able to leverage war-time sacrifices into seats in Parliament during the Trudeau era?
As for Prohibition .... OTL American. upper-crust ladies started the Women's' Christian Temperance movement to break drunks of bad habits they had learned in their homelands. Americans used Prohibition to oppress heavy-drinking immigrants from Italy or Germany during WW1. Sober workers also made better factory workers as the USA and Canada industrialized during the 20th century.