It's extremely doubtful it will be exactly 6TF. MS themselves don't know until the silicon is commissioned for press (late June/early August for November launches) they design it and aim for a ballpark and raise or lower clocks as such, they only certainty they have is they are confident they will hit 6TF/320GB/Sec as a minimum. But its doubtful it would be above 7TF, 6.2-6.6 is a reasonable assumption. They will want to hit $399 with a 1TB HDD and there's no reason to go all out, when from here on out, you aren't building consoles to last 6-8 year generations. You're building it for 30 months before it becomes the mid-range of your product line.
12GB is not an assumption, true it ain't confirmed (there's a reason for that, and it's the E3 megaton next year) the mock up has 12 memory chips (which makes no sense for 8GB of GDDR5 or any other memory) and if there's one thing that would scream "not a leap" it would be having the same amount of ram as a 4 year old console.
There's a concise difference between Scorpio and the PS4 Pro. The Pro is an extent of PS4 vanilla, the Scorpio is an early next gen console that just happens to play every XB1 game and has a 2 year head start. Question is has MS forced Sony to become the new Nintendo, consistently behind the tech curve, cos while i'm sure Sony will have a more powerful system out in 2019, Scorpios 16TF big brother will always be "only a year away"