I listened to the 1960s interview. Tolkien, alas, speaks far too fast and far too fluently for me to understand much of what he says, much less reflect on it.
In the first video (a clean-cut interview compilation), it is easier to understand what Tolkien says.
I don't think that trying to analyse "The Hobbit" theologically is too helpful. It's a story Tolkien wrote for his children; yes, there are clearly defined characters that are - broadly speaking - good and evil, but so what? Most (if not all) religions are broadly divided into good and evil.
If anything, Thorin is one of the most "fleshed-out" characters in "The Hobbit", in that he exhibits both good and evil. He only "turns" when he tries to find the Arkenstone, and even then, his character never becomes truly evil. True, he becomes paranoid; when it becomes clear to him that the Arkenstone is lost because of Bilbo, he threatens to throw Bilbo off the battlements, and even goes as far as to pick Bilbo up and hold him aloft. He then banishes Bilbo from his presence. But he realises his folly (albeit on his deathbed), and repents of it.
For those who say that it's easy to repent on your deathbed: consider that the Battle of Five Armies is written from Bilbo's point of view, and for most of it, he doesn't know where Thorin is or how to reach him. He also has no wish to, given that they parted in animosity, and who knows what Thorin would do to him.
The other characters in "The Hobbit" are not so easily defined; the dwarves are certainly under-characterised. Bilbo himself is an enigma; he accompanies the dwarves because Gandalf forces him to, and he helps them not because of his natural goodness (or lack thereof), but because he has no choice. Indeed, for a book entitled "THE HOBBIT", Bilbo's own thoughts on the quest are never made clear, except that he sees the dwarves as "the underdogs" and so wishes to help them. He has no particular reason to search for Smaug's treasure, and when it's finally found and he gains something from it (a dwarf breastplate), he feels faintly ridiculous -- but wishes he had a mirror. Are we to deduce from this that Bilbo is a narcissist? Probably not.
Gandalf himself is also an enigma in this book. We never learn where he comes from, or who he is, until "Lord of the Rings". (We also don't learn who The Necromancer is until LOTR).
For all these reasons, I'd say that trying to analyse "The Hobbit" from a theological point-of-view is pointless. Most of the characters are blank slates (except that they are broadly good or broadly evil), so you can assign almost any label you want to them.
Would you agree?