It's been a week now since this thread started and more data is available (sales ending November 28 and first week numbers for New Super Mario Bros in Japan). Based on this I expect the following outcome:
1. NSMB Wii (Having its Japanese launch included within the December numbers is a major advantage. Outside of Japan it should be able to hold its own compared to Call of Duty and Wii Fit Plus and its Japanese sales mean it can even take some damage there)
2. Wii Fit Plus (Although it got outsold by Call of Duty last week its sales are going up while Call of Duty sales are declining. Even if the decline stops in the coming weeks Wii Fit Plus should be able to overcome the gap by increasing its sales. But in the end it will be close, so it could go either way)
3. Call of Duty (Sales should remain high, but like already mentioned I think Wii Fit Plus will just sneak past it in sales for December)