When you spawn a family, you can't control which family member will be created, it's random.
So you need to create the object explicitly: "if currentweapon=laser, then create laser, else if currentweapon is missile, then create missile" etc.
Alternatively, you can ditch the family, combine all these sprites into one as different animations. Then on "Z" pressed, you spawn this one bullet sprite and only need to change its animation.