@youronlyone to sum up:
unlicensed deriv: ff
licensed but not
SPECIFICALLY approved: ff
author reads ff after its public and likes it: still ff
author reads before release and approves it: MAYBE not/less ff but hard to say
author uses own world based on your deriv of it? maybe not/less ff, hard to say / depends?
2nd author bases on public domain: ff- BUT, large mainstream works/disney arent called fanfic usually
regardless, i dont think copyright/licence is what determines fanfic status.