The party subject area should be used for any organization, individual, or member in the Customer 360 data model. It includes information such as name, address, email, phone, and loyalty membership. Reference: https://help.salesforce.com/s/articleView?id=sf.c360_a_data_cloud_party.htm&type=5

These two features are impacted by the timezone setting in the org Data Cloud is provisioned in. The segment schedule determines how often a segment is refreshed based on the selected timezone. The activation schedule determines how often a segment is exported to an activation target based on the selected timezone. Reference: https://help.salesforce.com/s/articleView?id=sf.c360_a_segmentation_schedule.htm&type=5 https://help.salesforce.com/s/articleView?id=sf.c360_a_activation_schedule.htm&type=5

These are the two dependencies that need to be removed prior to disconnecting a data source. A data stream is a process that ingests data from a data source into Data Cloud. A segment is a group of customers that meet certain criteria based on their data. If a data source is disconnected, any data streams or segments that depend on it will no longer function properly. Reference: [Data Sources], [Data Streams], [Segments]

Calculated Insights are predefined and calculated metrics that can help you build segments. Some of the benefits of Calculated Insights over Segmentation Operators are:
Calculated Insights are better suited for non-trivial calculations, such as calculating a Net Promoter Score as a percentage, which would require multiple steps and operators in segmentation.
Calculated Insights can query engagement data greater than 2 years, while segmentation operators are limited to 2 years of engagement data.
Calculated Insights are better suited for complex queries over multiple objects, such as joining data from different sources or aggregating data across different levels.

Dimensions are attributes that can be used to group or filter data in calculated insights. You can include dimensions as attribute data in an activation by selecting them from the available attributes list. Reference: https://help.salesforce.com/s/articleView?id=sf.c360_a_data_cloud_calculated_insights.htm&type=5