This is an exceptional well written article that I very much enjoyed reading. 
From other reading I have done I have learned that Fred Sasakamoose is the first verified whole-blooded "status” Indian. 
However, there are others that should be recognized. Paul Jacobs, a Mohawk from the Kahnawake reserve outside of Montreal may have played one game for Toronto in 1918-19 season (records are in dispute) some 35 years before Sasakamoose. Henry Maracle skated for the Rangers in 1930-31 but it is unclear if he was officially a status Indian. “Taffy” Abel, who started his career in 1924 was part Chipewyan native North American born in Michigan. Rene Boileau was played for the NY Americans in 1925-26 was billed as First Nations from Caughnawaga, Ontario. 
As much as there may have been others with a native or aboriginal heritage who played in the NHL this is not to take away from  Sasakamoose's accomplishments. Whether he was first, second or 10th his story is one we should all know and honour.