If Paris Jackson was to do an actual cover of one of MJ's songs which one would you like to hear her do? Personally for me it would be either "Stranger In Moscow" or "Little Susie".
Well, she sings a different style of music to Michael's, so I find it difficult to hear her voice in most of his solo songs. I do like your suggestions of "Stranger in Moscow" and "Little Susie" though - they would suit her voice, for sure.
Maybe something soft and melodic from The Jacksons would also work, like "Destiny", "Be Not Always", "Time Waits for No One".
None. She doesn't have the vocal range to pull it off.