Mauman
I also prefer Paladin over Champion. As long as you have one of them in the party, you can join the associtated guild. The spread of classes is so large in KotC2 (22 classes!) that it is very likely a player would have each guild covered. An exception would be for example is you did not take either Paladin or Champion, or if you did not take a Cleric or Bishop, or a Rogue or Bard, etc.
Search is used in the module. A character who has that skill will get the opportunity to notice things in conversations, here and there. I would not say it is super important.