You could potentially go the Voxel way.
We all have no idea what you are trying to represent, so it’s hard to give you suggestions…
If I were you I’d look into making a system that takes in the same data format you are given by whatever other software produces it and compute it in real time into what you need.
Not sure why you’d need UE4 for that either, it seems more of a basic matrix / C++ display sort of thing. especially if you need accuracy. unless you are somehow trying to leverage other functions like dynamic lights or something.
The character face changes are done with either mesh swaps, bone/animations, or morph targets. Basically it’s all smoke and mirrors.