This painting was a bit confusing as the Orthodox religion doesn't have saints or kings with multiple heads so three noses, three mouths
Probably representing the Trinity - father, son and the holy spirit. I have never seen it represented that way. I love the icon art. Always fun to see the sketch of a finished piece. A peak into the process of the artist. The embroidery is also very well done and I agree that the presentation is really well done. In addition to your points on the exhibit, I like that there are no figures or heads and faces with the clothing - keeps the focus on the clothing itself.
You might be right, I've never thought of that, but have never seen such thing either. Good point about the mannequins or the lack of them. I think proper mannequins would have changed things considerably and not in a good way.