Hi again.
For your first question:
You can blend the base locomotion (which you might need to cache) back onto the aimoffset to achieve the same layered type of isolation as any montage playing on a slot.
you can also use the same nodea with the same blend settings as any of those tutorials to achieve the same effect by just feeding the aim on top of the locomotion again.
For your second question.
Assuming you need the gun to sway as you utilize the iron Sights, while offhand and not on a rest pose (crouched or prone usually have no sway at all)
Your sway is in a predictable pattern irl. More or less a sideways figure 8 since you continue to adjust to remain on target.
You should be feeding those values to the gun, if you have the left hand attached to it.
If your socketed gun position is affected by the right hand, you can work on that IK bone to simulate the sway.
What I was referring to was a simple solution for getting the IK bone location of where the iron sight should be - to start to interpolate towards camera center from that location on the Z axis only.
Obviously a gun doesn’t just go up and down on a z axis, but that’s the first function needed to activate any type of iron sights… getting the gun sight in the center of the screen in a way that can be adjusted on every weapon without much or any effort…
Also, if you utilize the bone like that it becomes easier to offset the Z when you apply a scope or other attachments.