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.
In general, the answer is no. Let's take Snapchat as an example. Snapchat doesn't notify the story creator if someone rewatches their story. This is to give users the freedom to engage with the content as they like, whether it's just a quick look or multiple views. It also helps to keep the user experience simple and not overly complicated with too much tracking information.