Short answer
HubSpot's KB: SLA goals set response and resolution targets for help desk tickets. Using SLAs adds four properties, including Time to First Response SLA Due Date and Status. Time to first response in SLA hours and Time to close in SLA hours are populated for help desk tickets only. Goals based on combinations of ticket properties need Enterprise.
1. Availability
Help desk availability in my demo portal.

2. Escalation
HubSpot suggests a ticket workflow triggered by an SLA status property.