According to the Oracle Help Center, migration snapshots are used to migrate application artifacts and data between environments, such as refreshing the test environment from the production environment. Migration snapshots can also be used to restore the artifacts and data to the snapshot state in case of any issues or errors. The other reasons are not valid for creating a migration snapshot.

Lookup sets are used to associate source values, or keys, with target values that can be used in expressions for deriving properties or transforming properties in node type converters. You can configure keys and values in a lookup set for one or more applications. Lookup sets are not created during application registration, but rather as separate objects that can be shared across applications. Lookup sets are not used to group and filter nodes, but rather to map values between different applications or perspectives. References: Working with Lookup Sets - Oracle Help Center2

• This option is false because a hierarchy does not use all the data chain objects, but only a node type and a hierarchy set. A node type defines the nodes and properties that are used in the hierarchy, and a hierarchy set defines the relationships between the nodes.