Excuse me, can plug-ins be imported into flowchart files and edited
Could you explain your issue in a structured and detailed manner, so anyone has a fair chance to understand your use case?
Phrase your post so that we can follow your line of thought, step by step. Also please make clear what the use-case is you want to achieve.
So far I would understand your question as
Can bpmn-js or camunda-modeler plugins be included within
.bpmnfiles?
The answer to that is: No, that is not possible. Plugins (bpmn-js, camunda-modeler) are loaded as seperate ressources when instantiating. They can not be included in .bpmn XML files.