Hello??? JRRT, as a university student, never was anywhere but Oxford! (In the US, where I went to school 1966 to 1973, the term student was also used for those attending high school at least, in my case 1969-1973).
His first university appointment at the Leeds English School on 01 October 1920 was to a Readership! And he very much developed the almost nonexistent language section there. As a result of his efforts he was appointed to a new Professorship (aka "Chair") of English Language at Leeds on 16 July 1924. C. Scull and W.G. Hammond, "The J.R.R. Tolkien Companion and Guide - Chronology", 2006 two-volume edition (second volume being "Reader's Guide").
And if you mean, when you mention Carl F. Hostetter (not Hofstetter! And also not Douglas, I'm guessing you're getting that mixed up with the D.A. Anderson of the "Annotated Hobbit" among other publications), his "The Nature of Middle-earth", then you'd better get every punctuation mark right in your quotes, because I also have that book and can check them (and I also have Shippey's "Author of the Century", and the second and third editions of his "Road to Middle-earth").
But once again, you seem to have missed my point: I'm not arguing with any specific quote of yours from Hostetter or others. I take serious issue with your grandiloquent claims, as I feel you are implying, of what one should have read - a decidedly massive "syllabus" - in secondary and tertiary "sources" to understand JRRT's writings. To which implication I have a two-word reply: baloney slices.
JRRT's own term of "applicability", residing "in the freedom of the reader", from the foreword to the LoTR second edition, is basically a sharp slap in your face - and possibly JRRT's own too, which he may or may not have realized. That famous quote in a letter (to a Jesuit priest) about LoTR being a fundamentally Catholic work - never mind that in what JRRT may have considered exclusively Catholic (if he did so - my guess is yes) would have been in error, badly so as far as the other Christian denominations are concerned, and also to a lesser degree for the other "Abrahamic" faiths, he did not - could not - realize that for the human fundamentals that are to be found in his magnum opus, there are innumerable other applicabilities that the millions of his readers have found based on the experiences of their own lives.
And as to that "fundamentally Catholic work" - would JRRT have been able to write it (even more so the Silmarillion material he worked on for decades) solely on the basis of his Catholicism?
Hell, no!
Take away all of that "Norse stuff" that fascinated him al least in his youth, up to perhaps his middle years ... what would be left?