When you flip Pyke Dockside Butcher over from hidden, can you pay 1 red to have him ready and +2 this turn?

When you play a card from Hidden, you may choose to pay any optional additional costs specified on the card to receive their associated benefits. You do not pay the card's printed base Energy or Power costs.

1. Playing from Hidden

According to Rule 811.1.b and FAQ #6234, when you play a card from Hidden, you ignore its printed base Energy and Power costs.

2. The Optional Additional Cost

Optional additional costs are applied during the process of playing the card. According to Rule 356.2.b and Rule 357.2:

• Step 2 (Play/Finalize): You declare your intention to play the card from Hidden.
• Step 3 (Determine Total Cost): Because you are playing from Hidden, the base costs are set to 0. You then choose whether or not to pay the optional additional cost.
• Step 4 (Pay Costs): If you chose to pay the cost in Step 2, you pay it now.

3. Triggered Ability Timing

Once the payment is confirmed and the card is played, the card’s triggered ability—which checks if the additional cost was paid—triggers. Because the cost was paid during the playing process, the condition is satisfied, and the ability resolves to grant the associated effects.

Summary: When playing a card from Hidden, you do not pay its base Energy cost, but you must pay any optional additional cost during the "Pay Costs" step to receive the associated bonuses. If you do not pay the additional cost during this step, you cannot gain the bonus.

Note: I could not fully verify this ruling against the retrieved rules.