Oddly enough, while these four (belgariad, mallorean, elenium, tamuli) are not the best out there, they are among my favorites. I reread them every couple of years, and its always quick and fun.
There is a lot of stuff going on behind the scenes of the belgariad. While a lot of stuff was 'added' in spinoffs, a lot of your questions were answered in brief in David Eddings' 'campaign notes'.
Bare in mind also that this was not written in the fairly formulaic ways of most modern fantasy. David Eddings went back to the source material- late medieval chivalric romance, and reverse engineered it to create the style, flavor, and aspects of storytelling that created the Belgariad. In this way, he is like a much less time-intensive Tolkien.
In order to tell a story of this cosmic scope, you either have to be in the Gandalf's head (boring 'cause you know so much already) or the Frodo's. Which means clueless. If you want to see Belgarion come into his own, check out the Mallorean. You can tell the difference in the first chapter...
This is a line from David Eddings, and it says everything, or at least something, about how to read this series: "The use of archetypal myth in the creation of fiction is the literary equivalent of peddling dope."
Oh, and just to add a bit on the Elenium, not only is Sparhawk LG, he has the added flavor of being part of a LG knightly order known as some of the best torturers around. Harsh fellows.
Just avoid that new book by Eddings. Some good ideas in there, but I could tell which 1, 2, or 3 characters made up each character in the book, guess the plotline, and not tell who was talking with nametags, since they all had the same voice and personality of speech.
I ramble on to avoid doing work. Later,
