When a business analyst learns that another team also needs email integration in the near future, they should include that team during discovery. This is because including all relevant stakeholders early in the project can help to identify common needs, avoid duplication of work, leverage synergies, and deliver value faster. The business analyst should invite the operations team to participate in discovery activities such as interviews, surveys, workshops, observations, etc., and capture their requirements, expectations, and feedback. The business analyst should also communicate the project scope, timeline, and risks to both teams and manage any changes or issues that may arise. References:
https://trailhead.salesforce.com/content/learn/modules/salesforce-business-analyst-certification-prep/customer-di

The correct order of phases in the implementation lifecycle on a Salesforce project is analyze, build, deliver, operate. In the analyze phase, the business analyst elicits requirements, maps business processes, and creates user stories. In the build phase, the development team configures and customizes Salesforce based on the user stories. In the deliver phase, the solution is tested, validated, and deployed to production. In the operate phase, the solution is monitored, maintained, and improved based on feedback and metrics. References:
https://trailhead.salesforce.com/content/learn/modules/salesforce-business-analyst-certification-prep/get- started-with-salesforce-business-analyst-certification-prep

Explanation
The business analyst should confirm that the user stories are written effectively by checking that they can be easily prioritized and are small enough to estimate accurately. User stories are short and simple descriptions of a feature or functionality from the perspective of an end user or customer. User stories should follow the INVEST criteria, which stands for Independent, Negotiable, Valuable, Estimable, Small, and Testable. User stories that can be easily prioritized and are small enough to estimate accurately are more likely to meet the Estimable and Small criteria. Estimable means that a user story should have enough information and clarity to allow developers and testers to estimate the effort and time required to complete it. Small means that a user story should be simple and concise, and it should be able to be completed within a single sprint by a single developer or a small team.
References:https://trailhead.salesforce.com/content/learn/modules/user-story-creation/write-user-stories