Subject: With many (possible?) quantum results, is it possible for multple causes?

My understanding: 
Assuming either a standard interpretation of quantum physics or the many-worlds
interpretation of quantum physics, it is possible for the same event to have
multiple outcomes. 

My question:
Can an event have multiple causes to lead to its state?

Illustration: Using the famous Schroedinger's cat example, imagine two boxes,
each containing a cat in the situation described by Schroedinger's Cat scenario
(say one black, and one white). Now assume that similar to the gas device in
Schroedinger's cat example, each cat also has a computer apparatus (for fun,
I'll call it "Josh's Computer") that has a heart monitor connected into each box
to the cats. After the time for the half-life has passed, the light will come on
if both cats are in the same state (either both alive, or both dead). 

Whether Josh's computer lights up or not, we cannot know the quantum state of
either cat, despite that we can know the relation between the two cats. If we
know the light is off, we know there is one living cat, and one dead cat (but we
don't know which one's white, and which one's black). Or if Josh's computer is
lit, we know both cats are in the same state, but don't know what that state is. 

Implications (and question re-wording) in the standard interpretation of quantum
physics:
As I understand it, this scenario would mean that it is possible for an event to
have multiple causes. Is this a fair understanding?

Implications (and question re-wording) in the many worlds interpretation of
quantum physics:
As I understand it, any time a situation could be caused by multiple
combinations of events, each one of those chains of past events are realized in
a parallel reality. Thereby, in addition to the many futures to predicted by the
many worlds interpretation, there would be many pasts as well. 

Re: With many (possible?) quantum results, is it possible for multple causes?