Hi Jane,
Finding people after the last publically available census in Canada, which is the 1911 census, is rather difficult. However, here's some suggestions.
On pg. 5 of My Nighbour and Yours
http://www.ourroots.ca/e/page.aspx?id=3267950there's a note about a Pearl and Einer Mortensen. I don't know if this would be your Einer, but it's a possibility.
I'm not sure what the Winnipeg Post is either, but I doubt that it's a place of business. It's more likely to be a newspaper seeing as Einer was in the habit of writing a manuscript. He might have been referring to the Winnipeg Free Press.
What I find rather interesting is that Einer was till a fur grader in the 1920's. That's a rather late time frame for most immigrants - most fur trade happened in Canada in 1700-1800's. So you might consider querying the Winnipeg Free Press not only to see if they ever had him as an employee or "stringer" (free lance writer), of if they ever did a story on him.
Also, in Canada in 1940-41, all persons over the age of 16 were required to register. I've never tried to access any of these files but you can read about it here and possibly find someone who might do this for you.
http://www.ikweb.com/murduck/genealogy/research/sources/nrma...http://www.statcan.ca/bsolc/english/bsolc?catno=93C0006http://www.collectionscanada.ca/genealogy/022-907.006-e.htmlAnd yes, you have to search the HB Company records in Manitoba yourself, or hire someone to do it for you. I don't think they are housed anywhere else, or on microfilm that can be borrowed.
Good luck,
Bette