How to Change the Label of a Salesforce Custom Object in Marketo to Resolve Sync Issue

Hello,

I'm facing an issue with syncing a Salesforce custom object, Customer_Interaction, to both Lead and Contact in MKTO. 

(Simplified ER Model):

Problem:

When I enable the sync of Customer_Interaction in MKTO for the first object (either Lead or Contact), it works perfectly. However, when I attempt to enable it for the second object, MKTO returns the following error message:

Reference:

I found this link Error When Enabling Salesforce Custom Object, which suggests changing the label of the custom object (not the name) to avoid this issue.

Current Setup:

• The Customer_Interaction custom object has a one-to-many relationship with both Lead and Contact, meaning that a Lead and a Contact can have zero or many Customer_Interaction linked to them.
• Here is how I see the Customer_Interaction linked in MKTO, but note that only one is being synced: 

Desired Outcome:

My goal is to ensure the Customer_Interaction object syncs with both Lead and Contact, allowing me to filter and create smart lists, campaigns, and other MKTO activities based on this object.

Example Smart Lists:

1. Leads living in "Alberta" with at least one Customer_Interaction in Product X created in the last 30 days.
2. Contacts living in "Ontario" with at least one Customer_Interaction in Product X and another in Product Y created in the last 30 days.

Constraints:

• We would like to avoid adding or changing objects in Salesforce solely to support MKTO integration.
• We would like to avoid adding custom fields to Lead/Contact just to support MKTO integration.

Request for Assistance:

Could you please guide me on:

1. How to change the label of the SFDC custom object in MKTO, as the link above suggests?
2. Whether the information in the provided link is still valid and applicable to solve the problem described here?

Thank you! 🙏