Custom K2 Front-end publishing form (itemform.php)

1. I need a custom [login to view URL] for front end articles only (back end itemform should remain the same), see screenshot attached. 2. In the "Category" drop down menu, only language categories and "ALL" categories should be displayed. For example, if I have the following categories in the back end: AAA >>> language "English" BBB >>> language "Spanish" CCC >>> language "All" For example: If user is in Portuguese website, he will see only category CCC If user is in English website, he will see only categories AAA and CCC If user is in Spanish website, he will see only categories BBB and CCC Etc... 3. Categories for which user is not allowed to post should not be displayed (at the moment they appear in light grey. I don't want to see those light grey categories). 4. If there are no extra fields set for a certain category, the "Extra field" part should not be displayed at all in the form. 5. The form should be design responsive (desktop, mobile, tablet). 6. The form should remain multilanguage (don't amend the code too much, keep the language code strings). 7. All K2 features should remain. For example, if I decide no to display "Extra fields" in the form, and if I disable it from the back end, it should not be displayed in the form anymore (you should therefore keep current itemform code in the same way as it is now so I dont lose back end features). Important: I do not provide access to my website. You must work in your environment, and I will test the form in your environment.