Hi Ryan! Notifications without entering an escalation flow can be achieved by adding the user as a subscriber on an incident, via the “Subscribers” tab on the incident. This will send an incident notification, but will also allow you to announce the latest news on the incident to them and all other subscribers via the “status update” messaging feature on that tab.
Restricting the user’s ability to acknowledge or resolve can be done by granting the user the Observer role on the team to which the service / escalation policy belongs, or giving the user the global fixed “Stakeholder” role.
More info from the Knowledge Base:
Hopefully that helps!