I don't see anything mysterious in the late refreeze. There were posters in the melting season thread in late August/early September who demonstrated that sea temperatures in the Siberian Seas were way above any previous records, and drew the conclusion that refreeze will also likely be recordbreakingly late there. And so it happened.
Yep and the fact the Beaufort refreezing fairly quickly seemed quite an obvious prediction. Unfortunately we are seeing what will happen more and more in the future which is the early parts of refreeze will be very slow in regions which have very warm seas from the summer and the reality is, records are being broken in every month apart from September in recent years.
Of course an early Beaufort refreeze and a late Siberian refreeze does not mean the Beaufort will be slow to melt out next year and the Siberian side will melt out quickly again, alot will depend on the winter weather conditions and of course the summer weather patterns. If we get alot of high pressure this winter, the Siberian side could well be thicker than it was at the start of this year where the ice was thin and there was not much fast ice either.
HYCOM shows that the heart of the surviving MYI adjacent to CAA is now drifting MIGHTILY towards and into Beaufort.
I do agree with your second point but it is interesting to note that Beaufort is now closed, and not only is it closed, it is now being smothered in some of the thickest MYI in the Arctic (not that that is saying much, but in this case it is actually 2M+ thick according to HYCOM).
PS: looping through HYCOM, I think a key point in the Laptev's evolution over the past year was actually missed. There was an event in early January 2020 that is plainly visible looping the thickness maps, and during this time, the ice detached from the shoreline. This edge retreated rapidly northward, with minimal refreezing in its wake, stabilizing only around early April.
At that point, the melt season basically began, and the leading edge of the actual ice that had a real chance to form was already wayyyyyyyy north of Siberia in both Laptev and Kara.
This was tied to a major low pressure event in the Kara visible on the ESRL charts for 1/1-1/5 2020. So I would wager that if we see another major event like this in the same location this year, at any point between now and.... February? The same or worse is going to happen in 2021.
Basically, this LP event in the Kara seemed to trigger a massive katabatic wind into the Laptev, which destabilized the melt front at a critical point in its formation. And that ultimately cascaded into the Laptev's current virtually ice-free state on November 1st.