All of the options you've provided would generally be considered themes, as they convey underlying messages or insights about life and human experience. However, if we must choose one that is less universally applicable or more specific, "Loyalty to one’s friends is important" might be considered the least broad, as it is focused on a particular relationship dynamic rather than a more universal concept like justice or the struggle between good and evil.
Without further context, it's challenging to definitively state which might NOT be a theme, as themes can often overlap. However, if you are looking for a less commonly recognized theme compared to the others, that could be a potential choice.