@isotecviac2022, I’m not clear what you mean. All of your ES/OS nodes would make up one cluster. They do not replicate between them unless you enable replicas.
Do you mean to have four separate, but not clustered, instances of ES/OS? If so, why? That would be a very unusual configuration. What is your overall goal? What are you trying to achieve?
As for MongoDB replicas, you need a minimum of three nodes for a replica set, but you can use the mongodump command on a chron job to back up Mongo as often as you like.