1 Heiko Yamazaki, the General
Of course, there are stories of this thing completely changing the game, but in general, there is usually enough enchantment removal floating around that most of the time this will probably do nothing (expect possibly draw out that enchantment removal, but you dont usually want to approach the game like that, especially in multiplayer)
When they're gone, they're gone!
I listen to New Music Friday every week, not just from a competitive side, but because I genuinely want to know whats out there
Compare that to Dragon Vault at 21 cards and its not hard to see why the number of cards available is growing quicker and quicker
So Panharmonicon isn't the source of the second trigger, it's whatever the original source was triggering a second time