How would this scenario change, if there was a Big Bounce? And how would we potentially recognize alien civilizations preparing for that? And finally: in order

How would this scenario change, if there was a Big Bounce? And how would we potentially recognize alien civilizations preparing for that? And finally: in order to find out which of the two cosmological models is actually the correct one, we just set up SETI to find signs as to which of those two hyper-engineering projects have been undertaken - by civilizations that are a bit further in their cosmological understanding ;-)