Sky will probably assume GE will do the chase work for them on any stage they (GE) don't put someone in the break, so can save some work there until the last couple of km's.
If Sky are as smart as they tell people they are, they should be able to achieve podium and green jersey. Davitamon-Lotto achieved Green and 4th place in 2006 with a much weaker team than Sky will put together. So if Wiggins is good enough, he should be able to podium. Can he win with Cav in the team, probably not, but I don't think he could win if Cav wasn't in the team either.
If Sky are as smart as they tell people they are, they should be able to achieve podium and green jersey. Davitamon-Lotto achieved Green and 4th place in 2006 with a much weaker team than Sky will put together. So if Wiggins is good enough, he should be able to podium. Can he win with Cav in the team, probably not, but I don't think he could win if Cav wasn't in the team either.