No... God of War is not going to sell better than Uncharted 4, which might just hit the 15m mark.
As for the metacritic, it's possible. Could be as low as 86, could be as high as 94.
I'd probably say 90 MC and 7.5m sales.
Uncharted 4's first month NPD couldn't even top God of War III's, the new God of War will be even bigger in America and a lot of effort went into making the game more appealing to Europeans so if that's successful (I think it will be) the game could be as big or bigger than Uncharted 4, hopefully it'll be bundled as much too.
I'd guess between 90-95% average score (93%) and will sell 10-15 million (12.5m).