When SYNC redo transport mode is combined with Maximum Protection mode, it ensures that no data loss will occur (requirement 1). The physical standby can be converted to a snapshot standby (requirement 2) and later to a logical standby database (requirement 5), satisfying both transformation requirements. Transactions commit as soon as redo data is received by the standby database (requirement 3). The availability of the primary is not dependent on the standby database in Maximum Protection mode, as the primary database will halt if the standby cannot acknowledge the redo (requirement 4), thus indirectly ensuring its availability. It is also possible to deploy Real Application Clusters on both the primary (requirement 6) and the physical standby database (requirement 7), providing high availability and scalability.
ReferencesOracle Data Guard documentation detailing the requirements for different database roles, protection modes, and redo transport modes, as well as the capabilities and limitations of each configuration.

A logical standby database is part of Oracle Data Guard and allows the standby database to be open for read-write operations, providing additional flexibility. The requirements met by a logical standby database include:
Support for workloads requiring additional materialized views (A): Logical standby databases can support materialized views, allowing for complex data summarization and reporting workloads.
It can be used to create additional tables (C): Unlike physical standby databases, logical standby databases allow for the creation of additional tables that do not exist in the primary database, enabling custom workloads and reporting.
It can be used for Real Application Testing without affecting the disaster recovery capabilities (E): Logical standby databases can be used to test application changes, patches, and upgrades while still maintaining their role as part of the disaster recovery strategy.
Support for workloads requiring additional indexes (F): Logical standby databases allow for the creation of additional indexes to optimize query performance for reporting and analytical workloads.
Reference:
Oracle Data Guard Concepts and Administration
Oracle Database High Availability Overview

The process of performing a rolling release upgrade in a Data Guard environment using a logical standby database generally involves these steps:
* Raise the compatibility level on both databases (1): Ensuring both the primary and logical standby databases are operating with the same and correct compatibility level is essential before starting the upgrade process.
* Upgrade the logical standby database (5): Apply the database upgrade to the logical standby first, which allows the primary database to continue serving the workload without interruption.
* Restart SQL Apply on the upgraded logical standby database (2): Once the logical standby has been upgraded, SQL Apply must be restarted to apply the redo data from the primary database, which is still running the earlier version.
* Perform a switchover to the logical standby database (4): After confirming that the logical standby database is successfully applying redo data, perform a switchover to make it the new primary database.
* Upgrade the old primary database (6): With the new primary database now in place, upgrade the old primary database (which is now the new standby) to the new Oracle Database release.
* Start SQL Apply on the old primary database (3): Finally, start SQL Apply on what is now the standby database to synchronize it with the new primary database.References:
* Oracle Data Guard Concepts and Administration Guide
* Oracle Database Upgrade Guide

In the context of Oracle Data Guard and Global Database Services (GDS):
DGMGRL may be used to add the Sales configuration to the Prod pool in gds (A): Data Guard Broker's command-line interface DGMGRL can be utilized to manage configurations with GDS, allowing the addition of Data Guard Broker configurations to GDS pools.
Performing a role change with DGMGRL automatically notifies GDS which in turn activates the appropriate services (B): When a role change is executed using DGMGRL, GDS is automatically notified, and it then activates the services that are appropriate for the new database roles.
DGMGRL may be used to add a single database to the Sales configuration even if Sales is a member of the Prod pool (C): DGMGRL provides the capability to manage individual databases within a broker configuration, including adding databases to a configuration that is already part of a GDS pool.
Reference:
Oracle Data Guard Broker documentation
Oracle Global Data Services documentation