In Salesforce Revenue Cloud, when a new release is being deployed, it's important to test the implementation against the new release before it deploys to production. This can be achieved by:
Reviewing status.salesforce.com to determine refresh cutoff for the new release: Salesforce provides information about the refresh cutoff for the new release on status.salesforce.com. This allows you to know when the new release will be available in the sandbox for testing.
Determining whether your sandbox is on a preview or non-preview instance: Salesforce refreshes preview sandboxes a month before each major release. Regular, non-preview sandboxes are refreshed toward the end of the release cycle. Knowing whether your sandbox is on a preview or non-preview instance can help you plan your testing schedule accordingly.
It's worth noting that while Salesforce ensures that all sandboxes are upgraded, the timing of the upgrade can vary depending on whether the sandbox is on a preview or non-preview instance. Submitting a ticket to support when you want your sandbox updated is not a standard practice for preparing for a new release.
Reference
Test New Releases in a Sandbox Unit | Salesforce Trailhead
Salesforce Introduces Revenue Cloud to Help Businesses Accelerate ...

Incorrect future invoicing for an amended order product might be caused by the following scenarios:
A: Not contracting the Amendment Order: If the amendment order is not contracted, the changes made in the amendment order will not be reflected in the future invoices. This is because the contract is the legal agreement that specifies the terms of the sale, including the products, quantities, and prices. If the amendment order is not contracted, the original terms of the sale remain in effect, which may result in incorrect future invoicing1.
B: Having a subscription on the Contract be linked to an Order Product with one or more unpaid invoice lines:
If there are unpaid invoice lines linked to the order product, it may cause discrepancies in the future invoices. This is because the unpaid invoice lines may still be pending for payment, and if they are not resolved before the amendment order is contracted, the future invoices may not accurately reflect the changes made in the amendment order2.
C: Having a subscription on the Contract be linked to an Order Product with one or more invoice lines in draft:
If there are invoice lines in draft status linked to the order product, it may cause inaccuracies in the future invoices. This is because the draft invoice lines have not yet been finalized and may still be subject to changes. If these changes are not finalized before the amendment order is contracted, the future invoices may not accurately reflect the changes made in the amendment order2.
References: Salesforce Revenue Cloud documents12

Excellent Communication Skills both verbal and written (A): This is crucial as it ensures clear and effective communication between all parties involved. It helps in understanding the requirements, setting expectations, and conveying plans and progress effectively.
Being effective at planning, monitoring, and reviewing (B): This is important for keeping the project on track. It involves setting realistic timelines, tracking progress against those timelines, and making necessary adjustments to ensure the project's success.
Understanding design pitfalls and Mitigation actions to course correct (E): This involves having a deep understanding of common challenges that can arise during the implementation and how to navigate them. It also involves being proactive in identifying potential issues and taking corrective action early to prevent them from becoming major problems.
While having deep knowledge of competitor products and experience in a selling role with quota responsibilities (D) can be beneficial in certain contexts, they are not as directly relevant to leading a revenue cloud scoping session as the other characteristics.