Concerning the 'Multiverse' scenario - I agree with everything you wrote about it. As you say, the existence of alternate universe(s) is beyond scientific scrutiny, observation and testing...and therefore the hypothesis is indeed inherently unfalsifiable.
On the other hand, the existence of some meaningful 'Grand Designer' is equally unprovable.
However, I was really trying to get across the point that if the 'Multiverse' scenario is correct (in whatever type of form), then it could be that out of all the different permutations possible, that we happen to be in a random one which led to our galaxies forming in a way which gave rise to life as we know it...on our planet at least, so far.
But whether the fabric of overall 'reality' threw up a 'Multiverse' or just the single observable Universe we know about is not something I'm too fussed about. I don't believe that the 'Big Bang' we know about came out of 'absolutely nothing'...but I do believe that it's more likely it came about due to 'something' like a type of 'quantum fluctuation' that might make up the fabric of our unseeable overall 'reality' to begin with...rather than coming about due to some 'all-powerful', pre-existing deity.
Either way, I realise that my belief in a random, 'naturalistic' act of existence is as difficult a concept for some to accept, as the idea of a deliberate 'Creator' is for me...so we'll just have to agree to disagree in which 'faith' we choose to believe in.
Going back to these PROMETHEUS movies however, I would have preferred a storyline which kept the 'Xenomorph' eggs (along with the 'Queen') as having evolved in a truly independent, 'alien' manner on some far-flung planet with difficult conditions...rather than ending up as some kind of developed 'bio-weaponry' by 'tall humanoids'...which seems to be the direction Ridley's going.
Fair enough, if that's the way he wanted to set these creatures up...but I REALLY could have done without him involving the 'tall humanoids' as being instrumental in OUR develpment too!!
Mainy, I'm hoping that I end up actually caring for the new characters in ALIEN COVENANT in the same way that I did for the characters in ALIEN and ALIENS...or all the fancy kills and effects will be rendered meaningless overall. So fingers crossed for that.
HAPPY NEW YEAR to you and everyone else here.