How is Odin the Destroyer's 'INCALCULABLE MIGHT' trait interact with the new Pick-a-Power' stoppers (i.e. Leech, Darwin and Prodigy) in the new XXS set?

At no point is Odin picking or choosing a power with his trait, so it wouldn’t activate any of them.

Ranged Combat Expert is not an action. Running Shot is not an action. Those are powers.

I would suggest revisiting page 7 of the rule book on the definition of actions to understand how Incalculable Might works.