I'm just not sure about the TR numbers outside of US and UK. Let's say the game did the 550K (Nov+Dec) you estimates (i agree with the UK range). Adding something like 25% digital we get more 140K sales. To get to 1 million the game need additional 310K sales across the rest of Europe + Asia + Japan (physical + digital).
As i posted in the NPD prediction thread yesterday, the game performance on Germany doesn't look very good and the XB1 install base outside of US/UK is not expressive. Isn't Germany supposed to be the 2nd stronger market of EU? Here's the weekly chart position of ROTR in Germany:
Week 1 - 09
Week 2 - 16
Week 3 - 28
Week 4 (07/12) - 46
Week 5 - 53
Week 6 - 62
Week 7 - 86
If UK got ~150K sales i can see the Germany number at most at 50K. There's still a lot of games that must have been sold on XB1 weaker markets. That's why i think the US number is so important. With the great wom, and the reduced price i can see the can selling very, very well in the US in december.
I personally can't see the game reaching 1 million if the US number isn't at least 55/60% of the total.