One thing that stood out about Kirk (no pun intended) was his bio in the Playbill in which he noted, among his credits, that he was «Michelle Pfeiffer's dead brother in WOLF.» (mediamikes.com)
Another cool part of this DLC is that there is also an element of comedy that for me had parallels to Ghost Town and Weekend at Bernie's in that Geralt needs to assist one of his employer's dead brothers Vladimir. (impulsegamer.com)
For Professor X, he died at the hands of the Phoenix, but in the post-credits scene, it was revealed that he passed his mind into the body of his brain dead brother. (csmonitor.com)