Since multi-users access is not possible in EMR Notebooks, I'm wondering if it's possible to clone an existing notebook to enable developers to work in parallel instead of having to wait for each other to finish in order to get access to that notebook.
Instead of cloning or downloading the notebook, I will suggest to associate Git-based repositories with your Amazon EMR notebooks to save your notebooks.
In Amazon EMR console,Choose Git repositories, and then choose Add repository and follow the steps.
You can find the detailed precedure here.
Update on the question:
Yes, You can clone or merge code from/to remote Git repositories directly from your notebook. You can use this command for pulling/pushing within the notebook itself as well.
!git pull origin master
On running this for example, you will be able to see the files/notebooks from the repository to work on in the files navigation in both jupyterlab/jupyter-notebook