Kasmina's Transmutation vs. Gideon Blackblade
3.
From the card ruling on gatherer:


  If an effect causes Gideon to lose all abilities during your turn,
  he’s still a Human Soldier creature and a Gideon planeswalker.


and


  If an Equipment becomes attached to Gideon while he’s a creature,
  it’ll become unattached during the next upkeep that isn’t yours. The
  same is true of any Auras that become attached to Gideon that can’t
  enchant a noncreature planeswalker.