Edit: obligatory explanation (thanks mods for squaring me away)…
What you see via the UI isn’t “all that exists”. Unlike Reddit, where everything is a black box, there are a lot more eyeballs who can see “under the hood”. Any instance admin, proper or rogue, gets a ton of information that users won’t normally see. The attached example demonstrates that while users will only see upvote/downvote tallies, admins can see who actually performed those actions.
Edit: To clarify, not just YOUR instance admin gets this info. This is ANY instance admin across the Fediverse.
Not currently. Looking at the data it should be possible but I can’t make an assessment of how much coding effort would be involved. Export wouldn’t be a lot of work. Import would take a lot more consideration due to the need to reconcile data pointers and the effort involved in federating the changes, particularly when it comes to preserving timestamps.