Bell will play - and he *probably* will do so on merit. I think that most people would accept that he is someone who has been given quite good treatment by the selectors over the years, overlooking the amount of time it took him to progress from someone who scored the easy runs well to a batsman who was capable of shaping games. I think if we were talking about another series on the sub continent then we might consider his place, but when playing against a pace heavy attack in English conditions he is pretty much a safe bet.
I think the biggest questions really are over the sixth batting slot, third seamer and, just possibly, the balance of the side. Handling those questions in order:
I think its pretty clear that Cook, Trott, Root, Pietersen and Bell will start the series - the remaining question is, assuming that there is not a move toward five bowlers, whether Nick Compton takes the last slot (with Root coming in at six) or whether Jonny Bairstow comes back into the equation. Personally, I think that JB showed more in the South Africa game than Compton did in India, and he is the younger, more generally talented and long term option. I also think that Root is wasted at six.
The third seamer is tough - Finn and Anderson will share the new ball and Bresnan, much as the selectors want the bowler who was so good in the Ashes back, will take a long time to regain full fitness if the matter is handled properly. I suspect if he is fit that Stuart "I saw Andy Flower kissing Santa Claus" Broad will come back in, but I wonder whether a fit again Tremlett or Bunny Onions (whose accuracy would be of great value against a raw top order prone to nicking off) would come back into it.