I mentioned elsewhere that Tolkien was greatly influencd by the West Midlands translations done as part of his professional work. Sir Gawain and the Green Knight, for example, establishes the pattern for LOTR.
Tolkien also spent many years working with a colleague, E. V. Gordon, starting in the 1920s, on editing Pearl. He eventually asked Gordon to finish the work on his own and it was published in 1953, after Gordon's death. His widow gives Tolkien credit in the introduction. I found a 1st edition today. Christopher included Pearl in an edited volume with Sir Gawain and Sir Orfeo.
The importance is that Pearl is a story of redemption. This is best seen in the middle stanzas. Around a discussion of the Parable of the Vineyard
, there is a dialog about redemption. Pearl declares that all are equal members of the Body of Christ, which is a very Catholic view. The narrator disagrees and claims that God rewards individuals for their own good works, which seems to me a very Protestant view. Pearl then restates that redemption is equally available to all.I suspect Pearl's view is the one that Tolkien holds and that he considered Gollum eligible for redemption. This leaves the problem of the Ring's influence on Gollum. It seems difficult to argue that any of the "Ring Bearers" made a conscious decision to be controlled by the Ring. Possession of the Ring robs the bearer of his free will. I'm not sure how to reconcile this, but the dinner bell is ringing and I will have to return later.
I notice that Faramond didn't say that Sam actually believes that Gollum is redeemable, but rather that he is "asked to act as if" Gollum is redeemable. Those are two quite separate and distinct ideas. I think Tolkien presents us with "good men" like Aragorn or Faramir or Frodo or Sam or Théoden, who do "the right thing" without any kind of real "sight" into the certainties of Eru's design, and yet, through their actions, demonstrate a dynamic relationship with its unfolding consequences. They help insert "good" into the story and carry it forward to places unhoped for through decisions that often defy cold logic or self-preservation. It's not really important if they truly believe that Gollum or Wormtongue or Saruman is or is not redeemable; indeed, if they did, I would think that they would have a measure of saintliness that only Gandalf possesses (although I believe Frodo does attain a form of "heightened clarity" after the Quest is fulfilled). What is important is that they believe, deeply and unshakeably, as Faramond said about Sam, that they do "not know all there is to know of" the person that is at their mercy. And perhaps, of equal importance, they do not know all there is to know of themselves and their own role within the tale. 
