As the ODI series showed, speed is hardly the greatest of our concerns. The faster it is bowled, the faster it goes to the boundary. The very reason that those guys are in the Rest of South Africa team is that they don't have the accuracy to match the speed, in most cases.
Sehwag needs to come good in test cricket, and that means he has to last more than 5 overs. I feel if he doesn't get out in the first few overs, he usually settles down long enough to have a few lucky escapes and get a few runs on the board. I would go in with Jaffer to start with, because we need to play out the new ball too, not just get runs.
Tendulkar averages 55, Sehwag averages 52 and Jaffer averages 34. I don't know how you got an average of less than 10 from there. The fact of the matter is that you are judging that Pathan is a better batsmen than all of those guys by ONE match.
Here's a tissue to wipe off your sarcasm. Ganguly's been out of the side for a while, unlike Pathan who's been in the side and has been doing badly meticulously. Ganguly was brought back into the team to be drafted into the XI, whereas are pace 'battery' were brought in to show Pathan his last straw.