Can entries disabled by default in Guest Entries plugin and in section be enabled from the front-end?
Currently, that won't work.

The Guest Entries plugin looks at the plugin's setting for whether that entry should be enabled for the given section or not, not anything from $_POST.

https://github.com/pixelandtonic/GuestEntries/blob/master/guestentries/controllers/GuestEntriesController.php#L227