Congratulations on finishing LOTR. It looks like you have discovered
several of the dangling issues left there. Before one of the Big Guys
beats me to it, I would like to recommend you read Tolkein's Unfinished
Tales. In that book are the answers to the Istari, some Orc things, more
about Hobbits, and even a chapter on the Palantirs which I notice you didn't
ask about but should have. Another book with lots of answers is the
Letters of JRRT. It will blow you away. When we answer the hard
questions, we almost always have to refer to some of the background stuff.
Oh, and mithril is probably
titanium.
Some who wander are lost.
