I think the outcome of the first year (in your timeline) would depend heavily on the first two qualifying and racing sessions. If Vettel outqualifies and outraces him straight in the first two races, I think Fred could pop a vein.
I too think he could pop a vein if that were to happen, but I doubt he’d throw his toys out the pram, IMO he’s more mature now that back in 2007, as a person at least.
On the other hand, Vettel’s reaction to if Alonso out-performs him will also be interesting. Will he start to get worried/ be in denial of moving to Ferrari? He very well could, as for now his only real teammate has been Webber, and Fred is quite a step up from Mark.
That being said, I don’t think neither your nor my scenario will actually work out that way. Currently, Alonso is reaching the peak of his career while Vettel has time to grow. In 2014, Fernando will have the home advantage, and will probably out-score Seb. 2015 will be on equal grounds, and I firmly believe that they will draw on points, give or take. 2016, Vettel reaches the prime of his career while Alonso begins to age, that’s why I predict Vettel would come out on top in the final season together.
Of course, that is all if Vettel doesn’t extend his contract with Red Bull and actually moves to Ferrari; and that’s a big IF. In fact, F1 is IF spelled backwards.