Explanation
When onboarding multiple accounts from the Pending Accounts list, all the selected accounts must be associated with the same platform. This is necessary because the platform setting determines how the accounts will be managed within CyberArk, including the policies and behaviors that apply to those accounts.
If an account contains dependencies, those dependencies are automatically onboarded with the account. This ensures that all accounts and their dependencies are managed consistently and according to the correct policies1.
References:
* CyberArk's official documentation on Onboarding Accounts and SSH Keys1.

Explanation
According to the CyberArk Defender PAM documentation1, the Vault administrator can apply a new license file by uploading the license.xml file to the Vault Internal Safe and restarting the PrivateArk Server service.
The Vault Internal Safe is a special Safe that contains the Vault configuration files, including the license file.
The Vault administrator can access this Safe from the PrivateArk Client and replace the existing license file with the new one. After that, the Vault administrator must restart the PrivateArk Server service for the changes to take effect. This procedure can be done either from the Vault machine or from a remote machine.
References:
* Manage the CyberArk License - CyberArk