A small discovery to report: looks like someone from University of Toronto has kindly digitized a few back issues of Finnisch-Ugrische Forschungen, old enough to be out of copyright, and uploaded them on archive.org; findable e.g. under the keyword “Finno-Ugric languages — Periodicals“. Currently available are issues 1, 5, 6, 7, 9, 10, 11, 14, 15, from between (straightforwardly enough!) 1901 and 1915.
(Though the last one actually includes an article from a young Y. H. Toivonen (1890-1956), and which would according to Finnish copyright law remain under copyright for a while still… but one hopes the Toivonen estate will not consider this a terrible injustice.)