The ordering guide is available here:
https://www.cisco.com/c/en/us/products/collateral/security/email-security/guide-c07-736692.html
Based on that L-CES-O365P-1Y-S2 should work for 200-499 users.
The Cloud Email Security O365 Premium Bundle is a special premium security bundle for customers using Microsoft Office 365 as their mailbox solution. It contains:
● Entitlement to the service
● IPAS
● VOF
● DLP
● Cisco Registered Envelope Service
Note: It does not contain traditional antivirus because that is a built-in feature of O365.
Based on your requirement for scanning you can contact your Cisco reseller to include additional licensed features.
Regards,
Libin