Yes, the payment of a ransom or the payment at an auction does score points for the robber, as the counting figure is moving forward. Omission of that in the Order of Play was my oversight.
(Interestingly, payment of points for ransoming a follower or bidding in a bazaar does not count as a round of scoring for the purposes of the Messages.)
We don't have an answer for the situation of negative movement of the counting follower -- that's one of the questions that kettlefish has for HiG now. My guess is that the robber just keeps hanging on to the counting follower until the next positive movement, but that's not official.