Hi,
1. Modifications of the code are not recommended and supported by Appthemes.
2. You can hire a developer. There is a list of the community and certified partners
here .
3. At the moment this feature is not supported. You can assign tickets from the front end. I don't know if you had the chance to test the demos
1.
front end
2.
back end
Please let me know if you need more information.