Base Idle Animation, Random Idle Animation (from a vast range), Base Idle Animation, LOOP

… you need to watch more tutorials and use the editor more. Also, search for things. I’m sure you could.easily find what character ticking is.
it refers to the Tick group for the character actor.

You originally asked what to use instead of a delay.
Try a single frame delay.
you can do so by creating 2 delay nodes in a row and setting their delay time to 0.
however you will still be looping through the update animation event endlessly, and at the rate that the class default settings say you should…

use an animation notify to set that variable instead.
eady performance improvement…

Also, the transition back should be possible by getting the time remaining fraction of the state rather then the individual animations.
I think you have the individual aniamtions because of the blend bone by int node maybe, but are you sure there is no option for Idle Random when you search for “remaining”?