Explanation
A good way in Salesforce to verify that a record is syncing to a prospect in Marketing Cloud Account Engagement is to check that the Marketing Cloud Account Engagement URL field is not empty. The Marketing Cloud Account Engagement URL field is a custom field that is added to the lead or contact object in Salesforce when you connect your Marketing Cloud Account Engagement account with your Salesforce CRM. The Marketing Cloud Account Engagement URL field contains the link to the prospect record in Marketing Cloud Account Engagement that corresponds to the lead or contact record in Salesforce. The Marketing Cloud Account Engagement URL field is populated when a prospect record is synced from Marketing Cloud Account Engagement to Salesforce, or when a lead or contact record is synced from Salesforce to Marketing Cloud Account Engagement. Therefore, if the Marketing Cloud Account Engagement URL field is not empty, it means that the record is syncing to a prospect in Marketing Cloud Account Engagement.

The two activities that trigger a prospect record to sync from Marketing Cloud Account Engagement to the CRM are landing page submission and form submission. A prospect record is a record that contains the information and activities of a potential customer in Marketing Cloud Account Engagement. A sync is a process that updates the data between Marketing Cloud Account Engagement and your CRM system, such as Salesforce or Microsoft Dynamics. A sync can be initiated from Marketing Cloud Account Engagement to the CRM, or from the CRM to Marketing Cloud Account Engagement, depending on the activity or the data change. A landing page submission is an activity that occurs when a prospect fills out a form on a landing page, which is a web page that you create and host in Marketing Cloud Account Engagement to showcase your products or services, offer content, or register for events. A form submission is an activity that occurs when a prospect fills out a form, which is a web element that allows you to collect information from your prospects, such as their name, email, or company. Both landing page submission and form submission trigger a prospect record to sync from Marketing Cloud Account Engagement to the CRM, because they create or update the prospect data in Marketing Cloud Account Engagement, and Marketing Cloud Account Engagement pushes the data to the CRM

Users can be imported into Marketing Cloud Account Engagement from a CSV file or from Salesforce3. You can also manually add users individually or in bulk3. Importing users can help you save time and ensure consistency in your user management3

Explanation
You can define a user's role in two ways: during the import process or directly from the user record. During the import process, you can assign a role to multiple users at once by using a CSV file. Directly from the user record, you can edit the role of a single user by selecting it from the dropdown menu. You cannot define a user's role from the list view or through an automation rule. References: Create and Edit Users, Import Users

Explanation
The way the marketer can satisfy the request to permanently delete a prospect from Marketing Cloud Account Engagement is by archiving the prospect and then selecting "Permanently Delete" from the recycle bin.
Archiving a prospect removes them from the active prospect database and places them in the recycle bin, where they can be restored or permanently deleted. Permanently deleting a prospect removes them from Marketing Cloud Account Engagement and Salesforce completely and cannot be undone. The marketer cannot archive the prospect without permanently deleting their data, as the archived prospects still count towards the database limit and can be restored. The marketer cannot delete the prospect in Salesforce, as this will only archive the prospect in Marketing Cloud Account Engagement, not permanently delete them. The marketer cannot go to the prospect record and choose the "Permanently Delete" menu option, as this option is not available on the prospect record, only on the recycle bin. References Deleting Prospects