I said it's fine.
But if you insist - nobody lit his fuse. Doing so before knowing where and how far the enemy is seemed counter-productive. I don't even know how far a Bigglesworth could run in a turn. I don't think he could have reached the ghouls if they hadn't moved. But waiting a turn and moving up to the platform together would have ended in a cat-astrophe with the ghouls closing in on us.
Soo...
I have to bother you again as I have no idea how high the platform is. I count 9 steps. If a step is about 1ft that would be ~10ft. What movement does it cost to go up the stairs?
Anyway, we should not be stupid and run up there to engage that guy. The other 2 will attack us. We gotta retreat N after a ranged attack. I throw the dynamite, Cat shoots an arrow, Yulya uses Toll the Dead. Even if he jumps down, he should not be able to reach us if we retreat 30ft. Mrs. Bigglesworth could attack and prevent him from approaching us without provoking an opportunity attack - or having to waste an action to disengage.