Was toying around with the alpha, and found out the sneaking animation now is 1:1 of the old Alpha animation. 
Also the new aiming animation for the fussili rifle is also from the Alpha.
Sneaking animation Hitman 2:
Sneaking animation Hitman 3:
Sneaking animation Hitman Alpha:
Aiming Animation Hitman 2:
Aiming Animation Hitman 3:
Aiming Animation Hitman Alpha:
If there is any more brought back from the Alpha, Ill keep you updated.
(I think the new ICA woodsman covert is from the Alpha too)