Of course traps would work, but be careful how you use them. Remember that creatures move about those halls on a regular basis, so supremely lethal traps all over the place wouldn't make sense unless there's an easy bypass that the inhabitants know about. Any invisible or stealthed PC following one of those inhabitants might be able to easily spot those ways around the traps.
With all the secret passages around, the labyrinth's inhabitants shouldn't have much problem avoiding traps (nor the PCs if they can find the doors!)
The first time I ran the labyrinth my players came out in rough shape - those weasels literally sucked the life out of them - even without traps. But they also managed to split up in there which didn't help their cause.
Well my thought was using Wurst of Grimtooth's Trap in a few places, especially close by the secret doors to allow the kenku (at least) a chance to get around them. The Dire Weasels...haven't decided if they can spring those traps or not. We'll see
Thanks for the input.
Btw I was just thinking a few pressure plated traps since that would be easy enough for people to a) trip and b) Kenku to avoid.
Also I'm not aware of any invisible PCs just yet.
We as a group just got done with the first part of the 3FoE. The preists of Hextor nearly killed us but thanks to a fireball scroll and the second level spell "dance of ruin" we were able to turn the tide. BARELY!
We are now in a much better position that the boar and the half orc preist are now serving my wizard as zombies.
That boar has a +13 to hit and damage. The half orc serves as my body guard and personal valet. The way my DM describes the fury from the hextorits seeing one of their "high preists" turned into a mindless zombie under a wizards control is priceless. All the stuff from filges tower we used to our own ends. We even got smek to pay us to wipe out the cultists. Naturally we are going to betray him and be heroes in the eyes of the good people in town but hey gotta grab the gold.
I'd say go for the traps but be sure to give the party the exp when they walk over them without a scratch.