Hello Wiktor,
For points 1, 2, 3, 5, and 6, all these will require customizing the plugin. It even will not be possible for one with guidelines unless he/she is a good developer having knowledge in PHP, JavaScript, and WordPress. You basically will require customizing in several files.
For case 4.
WPERP usages default WordPress media library. So, this totally depends on WordPress itself. This works the same for your current uploaded media in WordPress.
WPERP just stores the data on WordPress media library and fetches when requires.
Thanks
