Basic security Setup multi Node Cluster Query

Hi Elastic team,

Below reference indicates, that before proceeding with basic security, the minimal security steps must be completed for every node in the cluster.

Does that mean we must bring down all ES nodes in same cluster (same cluster id) and run 'elasticsearch-setup-passwords interactive' for every node (Data+Master+Coordinating)
give all the same password for 'elastic' user?

Or would it be enough to bring down the Coordinating ES node alone (Which communicates with Kibana) and run 'elasticsearch-setup-passwords interactive'?
And will that apply user config, automatically to all nodes in the same cluster(same cluster id) with that Corodinating node, once its brought online?

No, you run elasticsearch-setup-passwords once for the whole cluster.

Thank you Tim!
Also, is it necessary to have TLS between Elastic Nodes, before configuring users and roles via kibana?

Hi Tim/ElasticTeam

Can you quickly confirm if TLS encyrption between ElasticNodes is mandatory, before user and roles creation via Kibana?