The random in BP_Character is evaluated only once when the Get Skeletal Mesh Asset is called. In order to get a specific one you should use a simple get Get:
However you must increment that index and the best way I can think of is to set the Index variable instance editable and exposed on spawn. This way it will show up in BP_Zeiger Spawn Actor BP_Character. From then on it is just a matter of storing an int and incrementing it every time you spawn a character.
I’ll still point that this is wrongly linked:
The timer will already re-trigger because of the looping…