@Anandha K
You can have more than 1 StandbyCS if required and it is mentioned in the below documentations as well. So you are good to go with the configuration.
https://documentation.commvault.com/2023/expert/102847_installing_standby_commserve_host.html
Note: Identical software must be used for setting up the production and the standby CommServe hosts. Ensure that the SQL Server version (including service packs) are identical in the both the production and standby hosts.*
Standby CS must have different hostname. Additionally FYI, an additional setting- sCSINTERFACELIST is configured automatically on the client groups during configuration to facilitate communication between the client and CS after failover to other nodes as well.
Reference: https://documentation.commvault.com/2023/expert/102842_planning_for_commserve_livesync_in_windows_environment.html
While failover can able to select which server will come active?
And yes, instance002 on Commserver will be acting as the failover clients and from ‘Failover Assistance’ tab on instancee02, you will find an option to select the standby CS to which you wanted to failover.
Thanks,
Naresh G