My opinion is to:
A) Sneak:
+ Animation: The egg is compressed down and reduce 0.5 block pixel
+ The aiming will be more accurated, easier for aiming, reduce scoping tme
+ The movement will be slower
B) Rush:
+ Reduce accuracty by 50%, harder for aimng
+ Player speed increase by 50%
C) Climb:
+ Move up on the ladder only
+ Slower to climb up than move around
+ Sneak to hold position, but less accurated than normal sneak