How do I create blendable animations for Unity that use IKs?

Question

So, I have two animations I have made. An idle animation and a swing animation:

I have tried to blend these in unity as a test for when I add in running, or sliding, etc. But I ended up with this:

The ideal in this situation is for the hands and hammer to move with forward kinematics.

However, when I am animating in blender, I followed a tutorial to set up a placeholder weapon with an IK in my rig. This makes animation far easier as I can move the weapon to move the hands, to move the arms, etc. However,

I want the final animation to be FK, not IK. Is this achievable?

These are my current weapon bones:

I honestly can't think of the best way to go about this. To recap, the goal is to have it so, when I set up animation mixing in Unity, with one animation controlling the arms and weapon (idle animation) and the other animation controlling legs, torso and head (attack animation), the movement of the body should not only affect the arms, but also the weapon and hands.

Answer 1

I solved this issue. My hands had been unparented from the forearm. This meant they worked for fixed animations, but once I tried blending, their lack of a parent meant they had nothing to move with.

I then had another issue where the hands would no longer bend. This was caused by needing to create a new mask for the new bone hierarchy.

I have moved the bones to FK and parented the weapon to the right hand for two-handed animations. I am now wondering how to animate more complex movements and realizing it will need a frame-by-frame FK limb positioning and a manual modification of the relative position of the weapon.. somehow.