After some further investigation, here's some additional and relevant information:

George Leicester's claim to the name "Lester" seems valid. The 1-27-1901 news clipping states Leicester resided in the area "one winter before the treaty was ratified with the Indians." That treaty would have been the LaPointe Treaty which was ratified in January of 1855. So this places Leicester in the area a good year before Mark Atkinson's earliest found mention of the name Lester for the river, as does Leicester's claim to have built the first framed dwelling in Superior. In a Google search, the phrase "George V. Leiscester of Baltimore, MD" comes up with one interesting mention of a person by that name in an 1897 issue of Pennsylvania Magazine of History and Biography who is compiling a history of the Lester name.  The following query appears in the Notes and Queries section at the end of the magazine:

LESTER family descendents and the allied names of Lister, Lyster, Leister, Leicester, or any name resembling these, whose ancestors settled in Virginia, Maryland, Delaware, Pennsylvania and New Jersey and the West. Write to George V. Leicester, 1120 Cathedral Street, Baltimore Maryland, who is compiling the Lester genealogy of England and America.
This query's date (1897) certainly correlates close enough with that of the aforementioned newspaper article (1901), and the fact that the Leicester in the magazine is searching out the origin of the name Lester gives further validity to the newspaper subject's claims. 

Hopefully, someone will be able to locate Mr. Leicester's original 1901 letter and subsequent paper in the historical society files in Duluth, but as far as I'm concerned I think the mystery has been solved.