Is it possible to copy a snapshot from one photo to another?
If not, is it possible to copy a preset from one photo to another without having to scroll through the whole list of presets (I have a lot of presets)?
I think the short answer is "no" (to both questions).
I mean, you can apply a snapshot, then copy the settings to the clipboard, then paste anywhere you want, but no direct single-step way that I know of..
Likewise, you can apply a preset to whatever photo you want, but you have to select it first (by scrolling through the list..).