My group has had two run-ins with individual party members of the FCP (Free City Party). One was with the rogue in the Feral Dog, and the other was with Khellek at the nice bar (I'm at work, so no notes).
The adventure offers them to be used as foils, and I'd like to know how other people have used them. For now, I'm holding them as a reserve as a way to prevent TPK, but at a price.
My party is now at 2nd level, but I still think they'd lose if they go head-to-head with them, so I haven't set them up for competition, and the party has been very careful to prevent anyone from learning about the WC (to the point of the barbarian taking off the +1 chainmail and stashing it in the minehouse before going back to town).
However, I'm in the process of developing a sub-plot where a PC's NPC sister becomes "involved" with Khellek, potentially leading the FCP to the WC ('cause they aren't finding anything in the Stirgenest Cairn).
So, any advice on how to give the feeling of competition without a full-out head-to-head fight, or screwing up with solving the item-based puzzles in the WC (they have one lantern, and are nearing the second one for the next session).
I would suggest let the party get a ways in the WC, and then come back after leaving to rest/sell items/whatever, and find evidence that the rival adventurers have been snooping around/looting the dungeon. The rival adventurers always manage to be in town when the party would have a chance to confron them; in town, where a fight would draw the attention of the guards. Then just have verbal confrontations. This should build animosity rather nicely. It also builds a precedent for why they would possibly come to the party's rescue in TFoE- the FCP has a history of following them around and looting their finds. The party would either be greatful for their salvation (not likely, especially if you play the FCP right), or will be even angrier at them. Then you can have them finally confront and defeat their old rivals at some later date.
The previews in AoW Overload are a bit vague. After the Champion's Belt encounters involving Auric, are the Free City Trio going to show up in other parts of the adventure path? Are they intended to be recurring NPCs or would it be okay for the PCs to defeat them at some point?