Does Traveling Merchant with Assault and Cleave get +3 Might when his move trigger fires?

Ruling: No, Traveling Merchant does not get +3 Might from Assault when his trigger fires. The showdown has not started yet, so he won't receive the Assault bonus until after his ability resolves.

Sequence:

• The Merchant moves to the battlefield
• The Merchant's triggered ability goes on the chain, and the Battlefield becomes Contested
• A Cleanup occurs
• Combat cannot yet start because there is an effect on the chain; Combat remains marked as Pending until the chain is empty
• After the chain resolves, combat begins and Assault applies

Nuances:

• The battlefield becomes Contested immediately when the Merchant moves, but this does not mean combat has started
• Combat is marked as Pending and cannot start while effects are still on the chain