You can't miss any events, only the rare bonus option within events that are completely optional. Almost all of them require Exhibition and/or Submission. And yes, you can replay events in the Gallery, however it will play as default, aka assumes your stats are all the minimum.
If you want, yeah. You could also just load a save before that event was played, raise those stats and play it. If it helps, there's a save page to the left of the first page that has autosaves, in case you've already saved over your manual ones.
