Except for one thing. Your question of relative importance and how the existence of talent might depend on aptitude.
You've practically answered this question anyway in your skeleton analogy.
Aptitude is like a bridge. And there are as many bridges as there are skills. Without the bridge the spirit can't get across and become a body; the 'talent' can't become a realised language.
The spirit without a body is nothing. The bridge with no one to cross it is just so much dead wood.
They need each other.