Do Repeat and Accelerate costs factor in for Yordle Explorer's trigger?

No, Repeat and Accelerate costs do NOT factor in for Yordle Explorer. According to a rule, effects that need to determine a card's cost for any purpose always use its base cost, even if that cost is altered or ignored as the card is played. Yordle Explorer checks the card's base Power cost (what's printed in the upper left corner), not the total cost paid. Additional costs like Accelerate and Repeat are NOT included in this check. For example, Miss Fortune (base cost: 1 Body Power) would NOT trigger Yordle Explorer even if you pay the Accelerate cost for an additional 1 Body Power. Yordle Explorer only triggers when you play a card that has 2 or more Power symbols printed in its cost box.