I assume it will become evident which writers are getting paid once paywall content starts going up. They’ll be the ones writing behind the paywall.
The decision for a piece of writing to drop between the paywall is mutual between Medium and the writer. Medium sends a blank pitch form to writers. The writers are free to submit a pre-written article or pitch a new one. If it’s accepted for the paywall, it’s mutual to both parties.
Yes, as far as I know from the letter and submission info I received, pay is one off based on the piece, not based on hits or views.
Thus far, Medium is still not making money. The plan, according to the letter I received, is that 100% of membership payments goes right back to writers.
Here’s the public page — some of that is covered there…
Hope that helps!