Graywater's Fixer itself doesn't have encore. Its ability applies only while it's on the battlefield.

If the mana cost of a card in your graveyard includes {X}, X is 0 for the purpose of determining its mana value.

Exiling the card with encore is a cost to activate the ability. Once you announce that you're activating it, no player may take actions until you've finished. They can't try to remove the card from your graveyard to stop you from paying the cost.

Opponents who have left the game aren't counted when determining how many tokens to create.

The tokens copy only what's on the original card. Effects that modified that creature when it was previously on the battlefield won't be copied.

Each token must attack the appropriate player if able.

If one of the tokens can't attack for any reason (such as being tapped), then it doesn't attack. If there's a cost associated with having it attack, you aren't forced to pay that cost, so it doesn't have to attack in that case either.

If an effect stops a token from attacking a specific player, that token can attack any player, planeswalker, or battle, or not attack at all. If the effect stops the token from attacking a specific player unless a cost is paid, you don't have to pay that cost unless you want to attack that player.

If one of the tokens somehow is under another player's control as the delayed triggered ability resolves, you can't sacrifice that token. It remains on the battlefield indefinitely, even if you regain control of it later.

A card, spell, or permanent is an outlaw if it has the Assassin, Mercenary, Pirate, Rogue, or Warlock creature type. It doesn't matter if it has more than one of those creature types; as long as it has at least one, it's an outlaw.

Outlaw is not a creature type. If an effect asks you to choose a creature type, you can't choose outlaw.

If an ability refers to an outlaw or whether a player controls an outlaw, it's referring only to permanents with one or more of the creature types specified above. Notably, it's not referring to any spell or card not on the battlefield. However, other abilities may refer to an "outlaw spell" or "outlaw card" in a zone other than the battlefield. Those abilities refer to spells and cards with one or more of the specified creature types.