It will take your opponent 32 turns to kill you in this manner, meaning that if your opponent has less cards than that in their library and no additional damage spells, there's no way for them to deal enough damage to kill you before you mill out
If myriad creates more than one token for any given player (due to an effect such as the one Doubling Season creates), you may choose separately for each token whether it's attacking the player or a planeswalker they control
Urza, if you dig into his history, was not the best person, to put it mildly
The best commons in Phyrexia All Will Be One You'd be extremely lucky to second pick any of these cards, so it's unlikely they'll come up often in a regular draft
As for Kaldring, the Rimestaff, you have permission to cast a snow card from your graveyard
Heavenly Demon Donquixote Pirates defensive disruption