I am perplexed, however, with your description of your daughter's occasional glassy-eyed incoherent states that seem to come "out of the blue". Not to alarm you at all, but this sounds like the description of a seizure disorder more than it does a child being angry or disagreeable. Are these episodes brought on by certain situations or can they literally come "out of nowhere"? A bear hug would not usually be sufficient to arrest even a minor seizure, so I am unsure as to my guesswork based on the little I know. Given what you have described, I would like to consult with both a children's behavioral psychologist and a pediatric neurologist to determine whether or not there could be a psycho-neurological basis to her behavior.
It appears that your kids do, in fact, have an established routine. If these living arrangements are relatively new and the routines in both households differ greatly, then confusion and anxiety may be present. Your five year old is old enough to benefit from seeing a talented child therapist who could help her identify the reasons for her behavior; this therapist must be someone who suits your daughter's personality and can form a comfortable bond with her. I wish I knew more about this situation but I hope my suggestions can bring you some direction. With this many caring adults, I'm sure answers will be found.