UI Panel Vs Widgets for creating animations in the sequencer...

Hi all! I am creating a series of animations in Unreal 5.2 where the 3D characters have 2D facial features and poses (think the faces of the characters in the Lego movies). They will just be poses to post, no inbetweens. I’m trying to create a UI for the animators that would make this simpler for the them, similar to a pose library plugin you would find in Maya, Blender, AE, etc. Mockup in this GIF here: https://imgur.com/a/oADTkKT

Obviously, that gif is overly animated for the effect, but you get the idea. They click on a face shape, it sets it in the timeline. I know I can set up a material where i can toggle through all the face shapes, but I’m not familiar enough yet with the Unreal UI and it’s abiltiy to make custom tool shelves. Is there an easy (non-c++ coding) way to create a Unreal Panel (similar to a floating panel like the content browser, seqeuencer panel, etc) that I could hook up to a texture parameter in the sequencer to change the value of that parameter?

Or would this involve widgets? Far as I can tell those mostly seem reserved for creating in game UI that float in the 3D level itself, not so much tools for animators using the sequencer to control things? Any pointers in the right direction would be greatly appreciated.

Honestly, even if I had to make a completely separate app outside unreal where I just click a shape and then it copies a keyframe that I could just paste on to the timeline and key it, I’d be okay with that in a pinch.