What behavior should an Administrator expect if a new send email step is added to the middle of an engagement program that has been running for several weeks?

In Salesforce, Contacts are deleted if an Opportunity hasn't been closed in 180 days. As a result, the corresponding prospects are marked as[[crm_deleted]] in Pardot. If the Request a Demo form is completed after that 180 day period, the prospect should be recreated as a Lead.
What automation tool should be used to solve this need?

LenoxSofts marketing manager wants to keep email branding consistent. They want Pardot users to be able to select this email content when building out engagement studio programs, one-to-one emails, and autoresponders.
How could this goal be achieved?

Creating or marking an opportunity as lost will result in the change of a prospect's score

When prospects register via a Pardot form, they will still receive GoToWebinar's reminder and registration emails.