Unlike Stoneblessed, Ruathar does not let you qualify for Elf-only options.
As for Polymorph any Object, yes, you could change a human to a drow or a drider. Human to Drow should be permanent (Duration factor 9 = +5 kingdom +2 class +2 size), but Human to Drider (or Drow to Drider) would require a second casting (the second one acts as Drider to Drider, which is permanent, even though the original transformation to Drider was temporary).