Now this one will probably be RAFO'd: I know you already said that there are four Shards outside of Ati and Leras in your other books. Could you tell us the numbers per book? Is just a standard two per book? Or do some have more than others?
Some worlds have more than others. You have seen the effects, influences, and work of four other Shards. One Shard, however, was no longer on the world by the time the story was told there.
I know that we've "interacted with two directly" (the pool in Elantris, and The Voice that called Lightsong back to life) that we've "seen it's power" (Dahkhor??) and another that we've seen their infulence (I have no idea on this one, though I think it might be whatever pointed out Aon Rao in Elantris to Raoden)
Nice guesses on most of those. You've got some things right. You've got some things wrong. The only thing I'll confirm (and I don't think I've said this before) is that The Voice is, indeed, one of the Shards of Adonalsium. (Endowment is that Shard's true name, by the way.)