Explanation
The Salesforce connector is a feature that allows you to integrate Marketing Cloud Account Engagement with Salesforce, a customer relationship management (CRM) platform. With this connector, you can sync data, activities, and campaigns between Marketing Cloud Account Engagement and Salesforce. You can only have one Salesforce connector at a time, which means that you can only tie one Salesforce account to one Marketing Cloud Account Engagement account. You cannot have multiple Salesforce accounts linked to one Marketing Cloud Account Engagement account, regardless of the number of accounts, the edition of Marketing Cloud Account Engagement, or the support from Marketing Cloud Account Engagement.
References: Salesforce Connector, Connect Marketing Cloud Account Engagement and Salesforce

To score prospects separately based on their interactions with different product lines in Pardot, the best approach is to assign a scoring category to each product line folder. Scoring categories allow administrators to segment prospect scoring based on interactions with specific types of content, aligning with different business units, products, or campaigns. By assigning a distinct scoring category to each folder associated with a product line, an administrator can precisely track and score prospect engagement relative to each product line.
This tailored scoring provides deeper insights into prospect interests and can better inform targeted marketing strategies.

According to the Salesforce documentation, the first step the user must take in order to change which email template is used in a running engagement program is to pause the program. A running engagement program is a program that is actively sending emails and performing actions to the prospects in the program. To make any changes to a running program, such as changing the email template, the user must first pause the program to stop the email sends and actions. After making the changes, the user can resume the program and continue the email sends and actions. Copying the original engagement program, changing the wait time for the template, or deleting the old sent email are not the first steps the user must take, as they will not allow the user to change the email template in the running program. References: Salesforce documentation

When a marketing user pauses an Engagement Studio program and adds a new recipient list, the newly added prospects will skip any Action steps the existing prospects have already completed, but will be evaluated on Trigger and Rule steps when the program is resumed. This is because Action steps are time-based and cannot be retroactively applied, while Trigger and Rule steps are condition-based and can be applied at any point in the program1. Reference: 1: [Engagement Studio FAQ]

Explanation
The automation tool that would best achieve this is to create a page action set to tag prospects as having viewed it and add them to a list. A page action is a feature that allows you to track and act on the behavior of prospects who visit specific pages on your website, such as your pricing page, product page, or thank you page. You can use page actions to perform actions on the prospects who visit the page, such as adding them to a list, assigning them to a user, or changing their field values. You can also use page actions to customize the content or layout of the page based on the prospect's attributes or behaviors2. To create a page action, you need to specify the URL of the page that you want to track, and the actions that you want to execute when a prospect visits the page. For example, you can create a page action that matches the URL of your pricing page, and tags the prospect as having viewed it and adds them to a list of pricing page visitors.