It's quite repetitive to copy/paste and modify /etc/map mappings for each environment as well as publisher/dispatcher and author, since content everywhere is almost the same.
Is there a tool already that allows to automate the mapping process for instances and paths generation under /etc/map folder ?
You can create the workflow launcher with a custom workflow process step that would copy the nodes from one etc map location to another and replicate if required.
But without writing some custom script there is no possible way of auto copy nodes from one location to another.
Since these are nodes you are setting in CRXDE lite - you can look at the possibility of writing a custom AEM service that creates these sling:Mapping nodes.
You can create the workflow launcher with a custom workflow process step that would copy the nodes from one etc map location to another and replicate if required.
But without writing some custom script there is no possible way of auto copy nodes from one location to another.