None of which are law or part of any "Declared Emergency". It has often been shown that legal definitions can vary from those in dictionaries. With regards to what the police can do, only the legal definition is applicable, which is why such things are defined in laws.
Again dispersing to where? They were already where they were dispersing to. Since the curfew is in place at the time of their arrest they certainly were not going to be traveling to any other residence. Therefore they were at the place where they were going to be spending the night. It would be interesting to know if they have applied this same standard to a single person who was outside smoking during curfew hours.It is also funny that you ignore what they were actually charged with, failing to disperse.
As an aside, it's kinda of kewl to watch the avatars of Excon and Dezaad go back and forth. Almost makes you wonder if they're some kind of MPD person.