First question : You're welcome

Second question : You can do it the same as I wrote above :
Code:

---

action assign_projectiles
{
   .....
   while (my != NULL)
   {
       moveMe();
       checkCollision();
       wait(1);
   }
   // or write all the above functions inside this action
}

---

With single action assign to different objects, each object
has their own movement and collision detection.

Third question : Sometimes, for example, you may refer to this
object within other actions, then you may need it.