Apocalypse pieces were available as blue or black variants. Rather than list every figure twice for each, only the Apocalypse figure is listed with a blue and black variant.
Initial release of the version with blue Apocalypse's left arm was available with or without the silver hose.
The Maestro is quite literally the Hulk's Alpha an Omega, his beginning and his end. Sometime in a possible future, the Earth was devastated by global nuclear war, a conflict that killed most of humanity, including its superhuman population. One of the few survivors was the Hulk, who found that he simply absorbed the radiation, making him even stronger, but also driving him insane. Calling himself the Maestro he eliminated any possible competition, and proclaimed himself ruler of the world.