There will be no overlapping displacements in v6 to cause this (or at least I think that's the issue) and sidewalks won't have this issue anymore (probably).
There is no way (that I know of at least) to make the hitbox follow the animation. The animation would need to be remade so the head doesn't move in a way that is very misleading. It would look ok as a crouch animation.
Yep, the plan is to have lots of signs so new (and old) players know where everything is without necessarily having anything memorised. I'll see for how many things I'll manage it.