Yep, how I did it and how Crytek does it is to just carefully place a camera and a animobject with the headless body of Nomad under it. I think there is a model where he is already holding a gun.
Now, to attach particles to either a AnimObject or AI requires a "CharAttachHelper"
These are under MISC in the rollupbar.
They are tricky to get working just right but the results are awesome.
Sorry I don't have the time currently to make a video tutorial on them, but here are the steps.
1: Place your AI or AnimObject in the scene.
3: Open the model of your character in the Character Editor. Note the names of the bones listed. They are stuff like "84 Bip01 L Hand" or "## Weapon_bone" (Those are the two most useful anyways)
2: Place a CharAttachHelper into the scene.
3: In the properties of the CharAttachHelper there is only one property: Bone name
4: Type the bone name minuse the starting numbers into here Example: "Weapon_bone"
5: Use the link tool to link the CharAttachHelper to the character.
6: Right click on the CharAttachHelper and reload the script.
7: You should now see two axis's. One is the charattachhelper, and the other is the actual bone you are linked to. A green line may be present between the charattachhelper and the bone location.
8: Now the tricky part. You need to as best you can perfectly align the two axis's together so that the X,Y,Z of the bone and the CharAttachHelper are in the same place and orientation.
9: Once that is complete, load the object you want your character to hold.
10: Link the object your character is holding to the CharAttachHelper, NOT the actual character.
11: reload the script of the CharAttachHelper again. If you got the bone location right your attached object shouldn't move much or disappear.
12: Move the newly attached object until it sits in the hand or your character the way you like.
13: For something like the flashlight image below, you can attach extra objects/entities to either the CharAttachHelper or the model you already attached to the helper.
14: Now anytime the character moves or is animated the attached object sticks to that particular spot.