As of now, Snapchat doesn't have a feature that lets someone know if you've rewatched their story. It's designed this way to give users some privacy when viewing content. For example, if you accidentally skipped a part of a story and want to go back to it, you can do so without the creator being aware that you're rewatching.
It depends. Some Snapchat features or third-party apps might give clues, but it's not always straightforward. Usually, there's no direct notification for rewatches.
Maybe. It depends on if they have any way of tracking or knowing that you rewatched it. Some snaps might have view counts or indicators, but not all do.
As of now, Snapchat is designed in such a way that when you rewatch someone's snap story, they won't be notified. This is part of the privacy and user - experience design of the app. It allows users to revisit interesting stories without the worry of the creator being aware of it. So, generally, no one can see if you rewatch their snap story.