Q: Do any Canadians appear on United States ("US") commemorative coins of the classic era?
A: At least one does!
The 1925 Fort Vancouver Centennial Half Dollar features a left-facing portrait of John McLoughlin (aka Jean-Babptiste McLoughlin) on its obverse. McLoughlin was born in Rivière-du-Loup, Quebec on October 19, 1784. He worked for Canada's Hudson's Bay Company and was its Chief Factor/Trader in the Northwest region and also served as Superintendent/Manager at Fort Vancouver from 1824 to 1845. The circa 1825 depiction of McLoughlin on the commemorative half dollar presents him at a time when he was a British North American Colonies/Canadian citizen.
John McLoughlin - Statue in US Capitol
After retiring from Hudson's Bay Company, he settled in Oregon Territory's Willamette Valley. It was there, in 1851 (per US National Park Service), that he became an American citizen. McLoughlin died in Oregon Territory in 1857 - approximately two years before Oregon attained Statehood.
1925 Fort Vancouver Centennial Half Dollar

For other of my posts about commemorative coins and medals, including more Quick Bits stories, see:
Commems Collection