For specifying ActionExecutors, we have oozie.service.ActionService.executor.classes and oozie.service.ActionService.executor.ext.classes. The former specifies the default ones, and the latter allows adding/overriding them.
For specifying the corresponding action schemas, we have just: oozie.service.SchemaService.wf.ext.schemas. This makes it difficult for users to add/override schemas. We should add a oozie.service.SchemaService.wf.schemas with the default schemas, where the "ext" config would add/override. This should be backwards compatible because both properties get loaded. We can also remove the workflow schemas from being hardcoded in the SchemaService class.
Similarly, we should do the same for the coordinators, bundles, and sla schema properties.