Do Bonus EXP, gold and stored items get transferred between parts?
Not exactly. Micaiah’s group, the Crimean army and Ike’s group all start with their own pool of Bonus EXP, gold and items. From Part 3 Chapter 10, the Crimean army and Ike’s group merge and their assets are combined. During Part 4, all three groups are able to share assets, regardless of which group you’re controlling.