I know what you mean by there is no closure for us. I have a sister who is for sure NPD.
I have had this new friend for less than a year who shows some sociopath traits but she is bi-polar. I notice she does what you mentioned above, that she doesn't really bring all her friends together which I find strange.
She doesn't seem to really care if she offends anyone or does anything wrong. I confronted her about something offensive she did and she denies it.
Again no closure, and they are trying to make you feel like you are either crazy or wrong.
It's a good excuse for me to end this crappy friendship.