Oh yeah, Toril was definitely in on Stefen's disappearance - I just like to fancifully headcanon about the whole thing, because truth, invention and forgetfulness seem to be themes with Stef, and he is very powerful when it comes to what he can do. XD

It does seem a little implausible that all mid-to-strong gifted mages in Valdemar would be suitable to be Heralds...surely some of them would just be flat-out terrible people. (Savil said that Staven would have been Chosen if he wasn't such a jackass, but there's no indication that he's mage-gifted specifically). Interesting to wonder what other strong mages did - maybe they often emigrated or became mercenaries.