To display the total amount of all the open opportunities related to the account on the Account page layout while using Advanced Currency Management, the consultant should use a record-triggered flow to set the value on the account. Advanced Currency Management complicates the use of standard roll-up summary fields due to multiple currency rates. A record-triggered flow can be configured to calculate the total amount of open opportunities and update a custom field on the Account record accordingly, ensuring the displayed amount is accurate and up-to-date.

No. A deactivated user doesn't count against your organization's available user licenses.

Creating a Slack channel to gather and discuss feedback from users is a good way to improve the rate of user adoption after a Sales Cloud implementation. A Slack channel can provide a platform for users to share their opinions, suggestions, questions, and issues about the new solution. It can also help the consultant and the leadership team to monitor user sentiment, address user concerns, and provide support and guidance. Verified Reference:
https://developer.salesforce.com/resources2/certification-site/files/SGCertifiedSalesCloudConsultant.pdf (page 20)
https://trailhead.salesforce.com/en/content/learn/modules/sales_admin_user_adoption/sales_admin_user_adoption_feedback