I think that was the case in the original event as well. But, if you don't spend anything, there is at least a chance that you can pick up what you missed in an event if the run a revival later. If someone had occasionally given Mistlehoe some practice over the last year, it would be easy for them to finish the event now. I didn't go crazy on mine, but my battles to get the outfits for the girls that weren't out for the original event were really short.
So, if you have Sunshine, from the Spring event, I'd raise her stats in case they have a revival for her.