Adele - I too hope you get to the bottom of things; one thing that I noticed in your recent post is that you say that Chloe and your children rarely have that much to do with each other...?
Obviously, every household/dog/child is different, but in my experience, dogs tend to get more stressed by unusual, or infrequently occurring situations than they do by ones that they are totally familiar with and which are proven to be non-threatening. You refer to Chloe as your dog, which suggests that her relationship with you is very different to other members of the household - which will undoubtedly influence her behaviour towards them.
Once you have got to the bottom of her current behaviour (whether medical or behavioural) and have a clear plan for the future; perhaps Chloe could begin to play a bigger role in the childrens lives? There are so many reasons why this is to be encouraged, and ultimately, it can only improve their relationship and help you rebuild your trust in her