The list looks good but I don't know if I'd run 3 belles. They're nice for luring and lowering defense, but if you run into anything that can negate it or has high WP you're in a trouble. At 30 stones I generally run 2 belles, 2 punk zombies, the convict, and sybelle. It only leaves me 2 SS but I haven't had a problem yet. There usually aren't any opponents left on the board after turn 5.
The other problem with 3 belles and sybelle is that the only killing power you have is the convict and seamus. The convict can be taken down fairly quickly, and while Seamus is a tough bugger it only takes a turn of dedicated fire to down him (and when the only thing you have to worry about is being hit with umbrellas I'd take a turn to just pop Seamus).
Just my two cents, but the raw killing power of two punk zombies will never let you down.
edit: I've never played with the copy cat killer, he may help, but his combat is so low I wouldn't rely on him for a lot of hitting power...