Are you guys confident enough to play with 6 batters? If so then I'd go with one of those two you mentioned. That being said how much more will Pathan add as a batter compared with the bowlers and then will his bowling be up to scratch.
I think we will play RP Singh or Munaf instead of Pathan. Right now, they're better than him.
The five bowler set up is an important one to consider because a four bowler configuration is harder to pick. For certain pitches, India would probably be forced to either omit Harbhajan or a valuable third fast bowler. In practice you could easily find neither to be the right choice.
Siddle is definitely the future of Australia but he won't be picked before Bollinger. Bollinger has been in great form since you last saw him taking 5 fers all over the place including in Pakistan when Aus A toured last year then carried that form into the domestic comp to be the leading wicket taker and then backed that up with wickets during the A tour against India.