Heh. So I was looking at the save to see what vassals should be edited out, and I'm not quite sure about Ireland and Wales. It seems to me that for Irish Dukes to seek the protection of the French King is maybe not totally stupid. They don't strictly speaking border each other, but there's a short body of water between them and France did historically mess about in Ireland whenever they fought the English. Shall we permit the French AI to keep these vassals? Let me know your thoughts. For myself, I'm inclined to let the Irish be French if they want to. Also Poland can keep its vassals in Germany, although not the ones in Burgundy.
As for time travel, how about this? China and Spain, with their greater resources, are actually further advanced than Norway in building Quantum Devices. However, since they are winning the Long War, they have no motivation to build one. So what they do is this: They make Devices of their own with dead-man switches. As soon as they detect the disturbances in the space-time continuum that the Norwegian Device creates, their own Devices activate. From there, your agents can do whatever they like!
Let's say, however, that energy considerations forbid sending back much more than one or two people at a time. Also, if you two could come up with your own reasons not to introduce gunpowder and steam engines in 1066, that would be good. You'll observe that the Ynglings have their reasons for not doing so, but I'm not sure what China's or Spain's reasons would be.