I, and probably the others who have not read Silmarillion, appreciate your summary, it "fills up the corners", so to speak. I would have believed that Elrond was there. Jackson's version works for simplicity, but I am happy to have you to fill us in .
According to the Foreword, The Shadow of the Past "is one of the oldest parts of the tale" and basically tells you what the problem with Bilbo's ring is and what must be done to fix the problem. It also foreshadows how hard it is going to be to "fix" the problem.
Like I said last chapter..."Poor Frodo!" (no Lobelia jokes this time!) :)