A:

add_hook("enter_freeze","disableGhost",function() set_ghost(0) end)

C: The distance from Tori's head to Uke's Joints. Returns an array.

function getDistance()
 distance={}
 hPos = get_body_info(0,0).pos
 for j=0, 19 do
  jPos = get_joint_pos2(1, j)
  distance[j] = math.sqrt(math.pow(hPos.x-jPos.x,2)+math.pow(hPos.y-jPos.y,2)+math.pow(hPos.z-jPos.z,2))
 end
 return distance
end

As far as I know it's impossible to get the exact momentum. You could try to get the acceleration with a = 2s/tВ for very short t. You have to figure out the mass somehow else.

e: My bad, momentum is m*v, not m*a. For v use get_body_linear_vel() and get_body_angular_vel(). Still the Problem with the mass.