I think Van Ness absorbing the other ghosts and him killing Victoria were two different things. One was, well, absorbtion, for which he needed to come in close contect with the ghosts, the other was a simple salt and burn (or just burn, in this case) so he could kill her from the distance. She didn't know it was coming, so he wasn't anywhere near her when it happened.

I loved your observations on how conflicted they are. Because they are conflicted. And they had just begun to find closure, only to find there is none yet. Sucks to be Bobby as well. Poor guy.