In Salesforce Revenue Cloud, the feature needed to split Order Products into different Invoice runs is the Invoice Group. The Invoice Group field on the order product is used to define more levels of grouping. After the invoice run groups order products by their billing account and payment terms, it then considers the order's invoice grouping. This process is useful for invoicing certain types of order products separately from your other order products1.
References:
* Grouping Order Products into Invoices - Salesforce
To split Order Products into different Invoice runs, the feature needed is "Invoice Group." Salesforce Billing allows for the customization of invoice groups, enabling the billing of order products that meet specific criteria separately. This functionality is particularly useful for separating invoices with different billing or payment terms and for consolidating several order products into a single invoice when needed. By defining an Invoice Group ID, users can control the invoicing process for order products more granularly, ensuring that invoicing aligns with business requirements.

To implement the user story of rewarding loyal customers with bulk discounts based on previously purchased quantities, the design of the solution should include the following components:
Contracts, Subscriptions and Assets should be populated with historical data. This is necessary to track the customer's purchase history and determine the appropriate discount tier for each product or service. Contracts, Subscriptions and Assets are the core objects of Revenue Cloud that store the information about the customer' s agreements, recurring charges, and entitlements. By migrating the historical data from the legacy system to these objects, the customer can leverage the Revenue Cloud features such as renewal management, usage- based pricing, and revenue recognition. 123 Discount schedules with Cross Orders checked. This is the feature that enables the bulk discounts based on previously purchased quantities. A discount schedule is a set of discount tiers that apply to a product or a product option based on the quantity or amount ordered. By checking the Cross Orders option, the discount schedule will consider the quantities from all the orders associated with the same account, contract, or subscription. This way, the customer can reward their loyal customers with lower prices for higher volumes. 45 References:
1: Revenue Management Platform & CPQ Solution - Salesforce.com US
2: Salesforce Introduces Revenue Cloud to Help Businesses Accelerate Revenue Growth Across Any Channel
- Salesforce
3: Give Discounts for Long SubscriptionsUnit | Salesforce Trailhead
4: Discount Schedules - Salesforce
5: Salesforce Revenue Cloud Trailmix - Trailhead

Legacy data migration is a critical aspect of a Revenue Cloud implementation and certain considerations can indeed expand the project scope:
A: Fragmented and incomplete information will need to be aggregated and validated, otherwise the solution will yield unexpected results: Data quality is a key factor in any data migration project. If the legacy data is fragmented or incomplete, additional effort will be required to aggregate and validate the data before it can be migrated to the new system1.
B: Extracting from multiple sources takes additional resources and time to access and process: If the legacy data resides in multiple sources, it can increase the complexity of the data extraction process. This can require additional resources and time, thus expanding the project scope1.
E: Large volumes of data take a longer time to load: The volume of data to be migrated can significantly impact the time required for the data load process. Large volumes of data can take a longer time to load, which can extend the project timeline2.
C: The creation of external objects will bypass the need for legacy data migration: While creating external objects can help integrate external data sources with Salesforce, it doesn't necessarily bypass the need for data migration. The data still needs to be accessible and in a format that Salesforce can understand3.
D: The Amendments and Renewals process will be subject to customizations: While amendments and renewals are important aspects of the CPQ process, they are not directly related to the data migration process3.
References: Salesforce Data Migration Best Practices1, Salesforce Data Migration Challenges3, Considerations for Legacy Data Migration4, Tips for Successful Data Migration2.

The key characteristics of an implementation partner leading a revenue cloud scoping session are:
A: Excellent Communication Skills both verbal and written: Effective communication is crucial in any project implementation. The implementation partner must be able to clearly articulate the project goals, requirements, and progress to all stakeholders. They must also be able to listen and understand the needs and concerns of the client and the project team.
C: Understanding Design pitfalls and Migration actions to course correct: An experienced implementation partner should have a deep understanding of the common pitfalls in design and migration and how to avoid or correct them. This includes understanding thetechnical and business implications of design decisions and being able to anticipate and mitigate risks.
D: Being Effective at planning, monitoring, and reviewing: The implementation partner should be skilled in project management, including planning, monitoring progress, and reviewing outcomes. They should be able to keep the project on track, ensure that all tasks are completed on time and within budget, and evaluate the success of the project.
While having experience in a selling role with quota responsibilities (B) and deep knowledge of competitor products (E) can be beneficial in some contexts, they are not typically considered key characteristics for leading a revenue cloud scoping session. References:
https://help.salesforce.com/s/articleView?id=000389713&language=en_US&type=1