Data Monitor vs Data DCP Reader for enabling Documents tab in UI

Data Monitor 

Data DCP Reader

Data Reader

Data Writer

All the above roles have been clearly documented as roles that does not provide UI access. However if the user has UI access these roles does influence UI behaviour.

For example:

Situation 1:

User has read-only-admin role: Read only admin role does not provide bucket data access, however read only admin and Data Reader role together will enable documents tab.

Situation 2:

User has query select role: With query select user gets UI access, but Data Reader role does not enable documents tab like in situation 1. It required either Data Monitor or Data DCP Reader along with it to enable Documents tab.{}

Ask:

1. Can we document how user can exactly enable just Documents tab and read documents from UI ?
2. Document if the Data DCP Reader role include Data Monitor privileges?