I thought I'd heard rumours about such things, it's terrible, and I'll do everything I can to help regardless of our prior discord.
You are right I know very little of the werewolves in Greyback's 'pack', but I do know a fair bit about werewolves themselves, and the mentality there.
From what I've witnessed and heard, Greyback runs an organization in exact 'pack' form. He is their alpha male, and what we've all gathered, Natasha is therefore the female. She is always with him, always working to impress him. They some how have been able to keep their 'minds' during a full moon, I have yet to determine how, as all of my wards have given no inclination to that sort of ability.
It seems, however, that even in their ability to keep their minds, they are only more ruthless and disarming. They see this ability as a better strategy to 'hunt', using it to uncomfortable perfection to capture their prey.
A normal werewolf uses it's wolf like sense to attack and feed, as any normal wolf would; however, it is only the most feral of werewolves that manage to go the distance and actually devour their prey (when it is human). This is not necessarily true with Greyback and his pack, while they hardly 'devour', they maim and destroy, leaving almost no evidence the victium was once human.
When transformed, werewolves are immune to many spells and jinxes; their new form has a unique magic of its own, even those that were once muggles will have this magical side effect in their wolf-state. A sure fire way to hurt a werewolf is silver. They are highly allergic to silver in either human or wolf state.
Fire is another good one, like most creatures (humans included) they have an aversion to fire and burning the magical or muggle way always proves effective.
One must remember, through all of this, that while they are dangerous in their transformed state, werewolves are still human. Twenty-seven days out of a month they are as human as you or I. Their minds are just like ours, and they share the same desires we all share. Wickedness does not come with the bite, that is something we press upon them or they were born with. In many cases, one can plead to the humanity within them- of course- there are exceptions. And worst yet, their does seem to be worrying trend with the older generations. They longer one is a werewolf, the more the mind is lost. Not necessarily to violence or evil, but the effects of a more wild spirit in ones blood seems to cause, in some, an almost schizophrenic effect. These 'episodes' of behaviour (lapses in memory, epileptic seizures, inability to communicate) can be controlled with calming potions and are minimized with regular 'psychiatric visits'.
I believe these episodes happen due to increasing guilt from prior transformations. Consciously after the transformation most werewolves cannot remember what happened during the course of a full moon. It is my belief that subconsciously they have some awareness and those that are good and decent human beings feel guilt to this, even if they have never harmed a human in their transformed state.
This is not true with many in Greyback's pack. As I stated, they can keep their mind during the transformation, but having no contact with the pack at all I have no idea if those have any decent in to insanity.
I have much more information, and if you need anything else, please, don't hesitate to owl me. Tonks is a friend and I hope she gets home safely.