I imagine that they grow up shrouded in ritual, each one a princess or a reincarnated infant wise man. I don't imagine they do much running around shrieking while they're physically immature... that's probably later.
Yes, but it is rare. When one elf gets a hangnail, the whole of the elven hosts gather and debate whether it signifies the impending decline of the elven race. Such rigorous investigation often reveals that the "inflicted" one was ultimately tainted and brought this fate upon themselves. Options at this point include execution or exile to prevent the spread of the "taint"