This is a fantastic mural, I love it! Not only is it well designed, but it has plenty of these things for us to ponder and figure out, which you also do so well. Yes, I believe it is very well fitting that it is painted on the wall of a hospital, and that origami heart is not only a pump for our blood, but is in fact a reflection of the soul, in the sense you described, with the help of the Alchemist.

Regarding the bird, I also want to add, that since their eyes are placed on each side of their head, they get to see both sides of an issue, although they can't get the full 3D experience like we do. As for the triangle, I have no idea, but I'm sure there is some interesting symbolism behind that too.