Hmm... the only other reference I can recall is from the 'Into the Shadows' anthology with Tailchaser by Paul R.Hume where the Mage Johnson makes a Tolkien joke but seeing as far as I recall Thorn isn't an IE, so I wasn't sure this fits your criteria....
“Indeed. Well, ah, Thorn, we require an expert in, shall we say,
physical security penetration. A burglar, in other words.” The dapper
mage grinned suddenly. “I realize that when a wizard looks for a
burglar, he’s supposed to hire a hobbit. Unfortunately, there are
none available.”
Thorn and the troll protested simultaneously at dragging Tolkien
into the discussion. The 20th-century fantasist was not well regarded
by many metahumans. After the first wave of Goblinization
in 2021, the stereotypes created in The Lord of the Rings had been
used to whip up public distrust of the new races, especially the orks
and trolls. A lot of elves also objected to the “airy fairy” image the
old talespinner had pinned on them.
Edit: there is mention of floor-toceiling
wall murals depicting scenes from the works of
Tolkien and other fantasy authors in the APN building during the Harlequin Adventure, but don't see anyone talking directly about it.