Could we use regular epics and sprint dummy epics together? Trying it out it seems like you can but is it intended behavior? Might it cause any issues?
Yes, in every way a dummy sprint epic would be a regular epic one, and its intended behavior is to be closed when all its contained user stories are also closed. It shouldn’t cause any issue as long as you know how the epics work.
I recommend you to create a demo project recreating your needs by using different approaches (fake sprint epics, sprint swimlanes, estimation tags, kanban/scrum… ), in order to choose the one that offer less friction to your team in their daily operations.
You may find interesting these links about the epic user stories:
