Some Questions in Migrating from activiti5.20.0.2 to flowable6.3.1

Hello,dear flowable’s passionate developers:
I’m a developer from China and I used activiti5.20.0 in the enterprise project but last week Idecided to migrate it to Flowable6.3.1。I did it in the weekend and the application is running successfully。Now I had some questions or problems,can you give me some suggestions。
The first one is that I used activiti modeler’s ‘editor-app’ folder in my frontend,now it isn’t work 。Can I cpoy the ‘editor-app’ folder in flowable6.3.1 to overwrite the activiti modeler’s ‘editor-app’ folder?
The second one is that my company has department,post (not only role,group) in business requirements。It means that I need to extend tree structure in my application。now,I thinking of two plans。The 1st is I extend attributes in the UserTask and implement the Idm engine by my requirements,so I shold edit the flowable modeler;the 2nd is that I use your DMN engine,then conversate outputs to my structure,it will make me hard to upgrade to your releases in the future.
Can you help me or give me some other better suggestions?

Best regards to you.