Hi there,
Is the contrary. Notifies are used to trigger starts or start/end events to the anim graph. In your case, for a given animation, you can send this:
Notify Starts = FABRIK Alpha = 1 (Enabled)
Notify End = FABRIK Alpha = 0 (Disabled) (or some of the rotation and location values changed)
To do that, you need to convert FABRIK alpha to a variable and go from there.
You can add notify tracks and have multiples anim notifies in a single animation.
Just as a side note, most of these animation packs look good as a starting point, but it might be necessary to learning how to edit some animations with sequencer.
Hope those videos will help you.