Our $2$ astronauts $($Arnold & Brunhilde$)$ form a physical system. They float with v$=0$ in deep space touching each other. Then they push each other in opposite direction with a constant force F$.$ Which statement about momentum in this system is incorrect?

they will move with the same speed in opposite directions, if their masses are equal

since total momentum is conserved their resulting velocities are zero

the total momentum of the system is conserved, which means that the two individual momenta cancel each other out

if their masses are not equal, their speeds will also not be equal

if the mass of Arnold is higher than the mass of Brunhilde, he will have a different momentum than her