The canine remains have helped me kill lilith in 2 of the 3 games I've played against her crew, they are a nice way to bring her down a peg.
I've used the autopsies a few times and they are kind of hit and miss, they do offer great ranged support but they are easy to wound, which even with 6 wounds, can be killed like they're nothing since they have the low zombie defense. I used them to best success with 2 belles luring targets into range then mowing them down with their fire and shafted markers from crooked men. I'm not sure if I'm sold on them yet since they don't drop corpse counters, however I haven't played them against too many living models and haven't played them against any guardsmen.
You may not be a fan of the belles, I know that I wasn't at first, but you will realize they are a huge utility to your McM crew with that 18" Lure, they also have 8 wounds and hard to wound so they have some staying power.
Bete is plenty of hard hitting on her own provided you don't let her die. I generally run 2 bells, 4 dogs, 2 crooked men, bete, zombie chihuahua in a 35ss game with Flesh Constructs and Rogue Necromancy to summon. When people see how much damage she puts out, some might try to play around her or hold back a bit, afraid of her popping in, which is enough to give you an edge.