Just started reading this, so I have a lot to get through, but a few minor points on the UK's part of the timeline that I noticed so far.
Tony Blair is identified as leader of the Labour Party in the early '90s at a time presumably preceding John Major's first general election as Prime Minister. IRL, Neil Kinnock was still Labour leader at the time of Major's 1992 victory and was replaced by John Smith, who died in 1994 and was replaced by Blair. While it's certainly possible that Labour might have replaced Kinnock and chosen Blair for whatever reason, I didn't see an obvious point of divergence that would have caused this to happen. Also, in the earlier portion of their careers, Gordon Brown was actually seen as the higher-profile moderate/reformer within Labour ranks with Blair as sort of the second fiddle.
Gerald Kaufman is identified as Foreign Secretary in early 1992, but it appears that Major is still Prime Minister in August 1992. Kaufman is a long-time Labour member whereas Major is a Conservative, and the Conservatives won majorities in both the 1987 and 1992 elections, so there would have been no reason to invite an opposition party member to join the Cabinet. Even there's a POD where Major called an earlier election that didn't go as well for the Conservatives and was surviving in a minority government situation, it's unlikely that they would form a "unity government" with Labour that would bring Kaufman or anyone else from Labour into the Cabinet. An agreement with the northern Irish unionists or even the Liberal Democrats probably would have been preferable for most Conservative politicians and voters in that scenario, unless the foreign policy upheavals have redrawn the traditional fault lines of UK politics.