Is there a possibility to show just a few specific columns from the table in frontend for authors/guest or non admins?
i just found shortcodes for showing a specific cell.
You can show Editable Fields for logged in users only.
Or you can organize Hidden Fields in your table. Then you can manage user roles who can use plugin at plugin settings – http://prntscr.com/gi5de0 and these roles will see your hidden fields in the back-end.