The Fediverse is open, everything you do on here is fully public.
It's why I prefer it over reddit, where who knows what really happens with all the vote manipulation and brigading.
To answer your question, it is all listed alongside upvotes on the posts if using mbin.
Yes.
I don't know of any clients that publicly show it, but the information is sent out as a json that can be read by anyone setup to receive them.