So what you're saying is that they have a Social Credit Karma system like Reddit does? I already hate it.
Not that I'm aware of, members can see what percentage others vote (i.e. do you vote 100% downvotes?) but that's about it. Mods and admins can see a reputation metric, but that's not forward facing to the public and simply a way for bad faith actors to be flagged.
Upvotes in meme communities do not add to reputation.
You can set it on a per instance or community scale as to if votes count, if you only accept votes from your instance, etc. It's actually a really handy option to have, maybe you want a community for only local members to vote on policy etc, well now you can filter it so only they can vote in here.
So far it's only Interstellar. The API has been release recently, so it's coming to a few more soon.
I use the PWA at version at the moment, works well on my phone.
If anyone is wanting to try out PieFed, registration is open on my instance and all are welcome.