Yes, that's exactly right about a previously published piece disappearing well down the profile. I think I might have mentioned that to you?
And yes, when people follow your pub, they see the stories you publish in it. It depends on other things, too, I'm sure - but don't ask me to explain M's algorithm! I just know it increases your chances of having more eyeballs on your work, so more reads, and more followers.
All else is the same - your topics etc. It's not exactly "forwarded to Medium" but it just means people who are searching for those topics are more likely to see your work - maybe that's what you meant.
And nope, publishers do not get any financial benefit for their efforts and time editing etc.
Any other questions, fire away!! 💜