So you have asked, so you shall receive. I can't guarantee that all of this is super correct, as I don't have it in front of me right now, but I will say:
Nemesis Weapons, as far as I know are Force Weapons. HOWEVER, because of how Brotherhood of Psykers works (A unit casts a psychic power as a singular entity) I believe this means that only one weapon can become a Force Weapon per turn (If you so choose to use it over Hammerhands), and the rest are power weapons. Still, nothing to sneeze at.
-Nemesis Halberd: +1 Initiative
-Nemesis Daemonhammer: +1 Strength
-Nemesis Falchions: Force Lightning Claws
-Nemesis Warding Stave: Power weapon that conveys a 2++ Invulnerable save. (I know. Madness.) They're 25-20 points per depending on the squad.
-Daemonhammer - This entry confuses me. There's both a Nemesis Daemonhammer and a regular Daemonhammer, but as far as I know, this one is a Thunderhammer with Daemonbane.
Psyk-Out grenades reduce morale of the unit they attack, I believe, but that one is the one i'm the most unsure on.