Yes the 'lockdown' news has happened, Wednesday is a formality.
The US election is a big story, especially this time round when it will have a direct impact on UK government policy leading up to Jan 1st.
Yes, although there have been occasions in the past when it hasn't been the biggest story in Britain on election day - 1984 is a great example when the race was a foregone conclusion and there was a traffic jam of big stories in Britain with the State Opening of Parliament and the CBI Conference (plus the first ever Turner Prize, you note).
https://genome.ch.bbc.co.uk/schedules/bbcone/london/1984-11-06
1992 was an interesting one in that although the election was a big story and led to a new President, the result seemed a foregone conclusion (there was an interesting article the other day about one-term presidents, and unlike Thatcher who was able to call an election after the Falklands War and win handsomely, Bush couldn't call one after the Gulf War which had been a success and had to wait, while the economy went down the toilet), and the autumn of 1992 was a huge period for British politics, just after Black Wednesday and with all the chaos surrounding Maastricht. Of course the 1992 coverage on the Beeb was notorious for the graphics going wrong and at one point predicting a landslide for Ross Perot.
1992, 1996 and 2000 were the only occasions I think ITV didn't do overnight coverage for the US elections, seemingly not thinking it was worth the bother and concentrating on the main bulletins (similiar to how in the mid-nineties they also stopped taking the Budget live for a few years and opted for an extended teatime news instead). I think 1996 was the last "boring" US election where the result was obvious from the start of the campaign and there was minimal interest in the UK.