Yes, it is possible to use an external LDAP server with ScienceBox.
This is harder to do with the uboxed version, as it is meant to be 100% stand alone. I can review that and check whether it is relatively easy to inject other configuration parameters to query your LDAP instead of the internal one.
For what concerns ScienceBox, consider we are revamping the project and we will have newer versions of the software soon. The old uboxed will be deprecated in favor of a version based on minikube, while the kubernetes support will be maintened and improved with the use of Helm charts.