It's amazing with as much as Jaina has been played this hasn't been asked before...
403.2A Resolve all abilities that trigger off the destruction of that character, then remove it from play. As part of doing so, remove all buffs and counters from that character's card and its Action Bar cards, drop it out of any form (303.4), and remove from play any pets (but not totem tokens) it summoned. This is different from destroying those pets.
It specifically says that "this is different from destroying those pets" so therefore if you kill Jaina, and then remove from play the Greater Water Elemental, it wasn't destroyed, therefore it doesn't ready.
That's the way I read it.
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