You can't use MSI for contact-like COs that aren"t synced to Marketo,,, but your phrasing still seems to be leaving something out. Where do these COs live? What do they do from a marketing perspective?
Thank you for the reply! These COs live under Accounts within Salesforce, and are syncing certain fields to Marketo. From a marketing perspective, these function as B2C leads whereas our traditional contacts/leads are B2B. It would be valuable for us to leverage MSI for both sides. Hope this helps clarify.