If you only want to have 1 character of each type on the screen, then you can "recycle" them. Instead of destroying characters, move them off-screen. When you need to spawn, pick all off-screen family members and pick 1 random instance from them. You will also need to modify all other events, make sure that they are only picking active characters.
It can also help to disable collisions for inactive characters, so that they won't trigger any "On collision" or "Overlapping" events.