I just checked a few Toronto city directories. Turned up nothing useful but did find a puzzle.
1910, 1911 - no Checketts or Chicketts
1912 - Checkett James B, wtr, b 739 King w
A check by address has "Tear Geo, rest" associated with 739 King St W where this Checkett is a boarder.
1913, 1914 - nothing
1920 - Checkett Jas, rms 444 Gerrard e
1922 - nothing
1924 - Checkett Jas, h 5 Currie pl
So there's no trace of the sister and no certainty that the Checkett at 739 King is yours.
Interlake Tissue Mills was started in 1912 according to
http://www.cellutissue.com/about-interlakepaper.html.
There's a picture at
http://www.nfpl.library.on.ca/nfplindex/show.asp?id=101111&b=1 which is dated as "ca 1910".
mat