Absolutely agree with #3! I just finished Les Mis (took me like 6 months!) and had the exact same impression about Thenardier/Gollum parallel. To me it seems likely that Thenardier was an inspiration to Tolkien in creating Gollum and the theme of "how do you explain 'evil' in a world good God created." I was only looking from the point of view that there is an "evil" character that unwittingly plays a role in the success of the "good" characters. I immediately thought of Gandalf conjecturing to Frodo that Gollum might play some kind of role in the quest to destroy the ring, and that Frodo should not harbor thoughts of the harm/destruction of Gollum. As we know Gollum's delirious greed quite unintentionally saves the day in becoming the ultimate agent in the destruction of the ring. Thenardier's greed unintentionally saves the day by unlocking the sewer for ValJean/Marius escape from probable death (at least for Marius). Also Thenardier and his greed act as the agent to reveal to Marius his rescuer and the ultimate reconciliation of Marius/Cosette with ValJean at the latter's death at end of novel. I'm kind of literarily lazy, but I', sure there are several other more subtle examples where the despicable actions of Thenardier are key to the ultimate "happy ending" to the life of ValJean and Cosette/Marius.
So yes a despicable character driven by intense self-centered greed [that the reader would like to see killed!] ultimately plays a role in God's ultimate plan that us lowly human bit players cannot understand at the time. Although to me Thenardier seems a much more one-dimensional "bad" guy whereas the Gollum/Smeagol thing is more complex and realistic. With the pervasive theme of redemption and how "bad can always become good" in Les Mis, I found it interesting that Mr. Thenardier remains a bad apple even to the very end with his resumption of petty crime in America. Come to thing of it, it seems like Eponine, in the end, is the Smeagol to Mr. Thenardier's Gollum - she truly loves and cares about Marius and we see her in a good light.
Another more obscure Les Mis parallel to more modern media that came to my mind ... when ValJean escapes his bonds in Thenardier's den of criminals and warns them they can do nothing to scare/threaten/harm him, and then demonstrates this by searing the white hot fire brand into his own skin. This reminded me of the Keyser Soze folklore in "The Usual Suspects" where the rival gang is threatening Soze with his family at gun point, and Soze proceeds to slit his own wife's throat and kill his own children and "shows those men of will what will really was."