Yes, I did not read closely enough. You referred to new medicare for all plans, while I responded recalling similar false accusations against Obamacare. Some of these new proposals do not allow duplicate plans. Nevertheless, I don't think this particular objection makes them DOA. I believe this is an objection that could be overcome with discussion.
This is not correct. There was no prohibition on private insurance. Rather, all would have been required to participate in the public plan to spread the risk. That's the only way it could work. If someone wanted to also pay for a private plan, that was allowed.