While they have the being in play twice thing and the graveyard synergies things going on they are not sticky, they don't need killing twice
There's no upkeep cost and no way around it with the exception of removing Moat itself
If, during a player's declare attackers step, a creature that player controls that's been goaded is tapped, is affected by a spell or ability that says it can't attack, or hasn't been under that player's control continuously since the turn began (and doesn't have haste), then it doesn't attack
The release of these cards absolutely rocked the game and its player base, and it brought a completely new way of playing and interacting in the game
Look for great cards like: Set Name:Zendikar Rising (ZNR)
Whenever she quests, a player can return a character card from the discard pile into their hand, a way to potentially draw powerful options back into the fold