Good afternoon and welcome to the Events Calendar forum!
Thank you for your interest in our products.
We’ll be glad to answer your questions.
Distinguish events that are ongoing vs. one-time only
Yes, you could do that using either Event categories or Recurring events (available with our Pro premium add-on). You can even use both techniques at the same time.
I would also recommend using the third-party the Events Calendar category colors: https://wordpress.org/plugins/the-events-calendar-category-colors/
Show events based on priority of event date
I am not sure which of our Calendar views you have in mind (list, photo, month, etc…). But typically, the events are by default shown by the closest date to the current day.
Furthermore, you can totally customize every view to your liking.
You might want to read our Themer’s guide to get a sense of how that works.
Highlight specific events – please note each campus will need to specify priority events
I believe using Event Category colors or the month view’s sticky post could act a solution.
Let me know if that helps.
Have a great day!
Geoff B.