Failing to get a simple look left/right animation to work

I have a character with a skeletal mesh that will remain in an idle pose (like a statue) and the head will turn towards the player. However I am having difficulties setting this up. Firstly, I’m not sure if there’s any difference between a blendspace and an aim offset for this scenario. I know most times when you want to have a character look left/right an aimoffset is probably the way to go. But since my character will be performing no other animation it doesn’t seem beneficial.

I have tried setting this up as both a blendspace and an aimoffset and both have failed. When I create the blendspace (or aimoffset) and move the preview between left and right, the head does not turn. I believe this may have something to do with how I created the left/right animations.

First I took a character idle animation and cut out all but 1 frame so the idle is absolutely still (no breathing animation). Then I duplicated it, turned the neck 15 degrees, added a keyframe and saved it. Did the same at -15 degrees. But although I can open these left/right animations/poses and they look correct on the character, they do not impact the mesh in the blendspace.

Not really sure where to turn for this or what other information would be beneficial to provide. Any suggestions?
Idle:


Left:

Right:

Blendspace:

Updating to post my resolution: I exported the idle animation and imported in blender, edited my keyframes there and exported it. Worked in UE4 after that. Not sure why.

Whenever you have a single bone that needs to rotate on a single axis you can always use a modify bone node in the animation BP and feed it a v3 with the proper value.

So there’s 3 essentially equivalent methods to pick from.

AO requires 2 animation poses.
BLEND requires 2 animations.
Bone manipulation, requires decent coding.