I am familiar with leaderless group dynamics. Most of our paddles operate under this model. That is fine with me. Where our community runs into problems is with the implementation of "everyone has responsibility AND no one has responsibility". Logically, it cannot work both ways unless you define specific responsibilities and the thresholds at which point no one becomes responsible for them. This definition process would need to happen in advance and everyone must understand and agree. Your posting gives several good examples of responsibilities and expectations.
I would suggest that on our paddles no one is taking any responsibility. We'll help if we can but pretty much, you are on your own.
Most of our "Leaderless Paddles" are essentially solo paddles with other paddlers in varying proximity. There is little added safety in this type of event as compared to solo paddling. Additionally, some folks will push the envelope further because they are in a group. This will not always end well. We have had people swimming, separated from their boats and nearly washed out to sea with no one who was close enough that they could have filled out an accident report.
Leaderless groups are fine during milder conditions and when things are going well. However, they have significant limitations.
I would submit that we move our leaderless model to a team like model as conditions and paddlers' preferences require. The key differences being that the group commits to staying closer together and watching each others' backs a bit more closely. Team paddling provides significantly increased safety, faster skill development and I find it more socially rewarding. The Tsunami rangers believed strongly in the team paddling approach and spent years honing techniques to enable team paddling even in ridiculous conditions. Navy Seal Teams and Coast Guard Rescue Swimmers also venture out in the same conditions as us. They are strong proponents of "No Man Left Behind".
We can remain leaderless and still be a team.
The Connyak BBS