Okay… I was wondering if I was going to need to invest more narrative on that point:
Looking at scenario (2) first, if a YEC wants to propose that Neanderthal (or other interbreeding) could change our analysis of possible bottlenecks, he would have to do two things at once:
a) that Neanderthals were an equally legitimate part of the human race per Genesis (I have very rarely found a YEC willing to do so); and
b) having done so, the YEC must somehow show that the Neanderthals introduced a completely different biology - - all the while being on par with the view that they are equivalent to Sapiens.
As for Option ©, it’s the same kind of issue… but instead of arguing for a different biology, the YEC has to simultaneously equate the contributors as “on par” with the rest of humanity … and yet also dramatically speed up mutation rates that the conventional analysis assumes for humanity.
Whenever we discuss how the scenarios could be changed, we really need to validate the proposed change with the likelihood that a Young Earth Creationist would tolerate the scenario change. Nothing important is accomplished to argue that there can be a single pair bottleneck one million years back in time when we can’t find any Creationist who accepts a million year time frame.
And if we find a creationist who says he endorses a million year time frame, the next logical question is how does he justify a million year time frame (and thus Rejecting the premise of 6 days of creation) while at the same time insisting on Special Creation a million years ago? This kind of creationist is neither Fish nor Fowl, and will be repulsed by Evolutionists (because of the feature of Special Creation) and by Creationists (because of the rejection of 6 days of creation).
Rather than making the BioLogos “spin” more palatable, it makes it likely that we will double our opposition, or at least double the apathy of a vast swath of our potential audience.