You can type with emojis by pressing Win + period and picking some. Only a few are supported, like the heart eyes and smiley face. As for adding those other movement mechanics... sneak doesn't fit the play style, rush (what?) you're already going pretty fast, as for climb, maybe.
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