Michael, I think you have a basically complete list of whats required to succeed in embedded design. While I do not exactly disagree with a couple of points, here are my comments.

One point you make re laying out PCBs, I think should be global. If you do not have a given skill (physical such as mounting ultrasmall components or artistic such as PCB layout) you MUST have the ability to guide those that do it for you.

1) 2) 3) 4) 5) 6)
Amen

7) Skills with prototyping and fabricating circuits.
I do not have such skills with the components used today; however, I have a wonderful production dept that takes care of that for me.

8) Ownership or access to a minimal tool set ... mimimum an analog type of oscilloscope....
I think it would be better to invest in a used digital scope, many signals in embedded are too rare to show up on an analog scope.

9) 10)
Amen

11) 12)
Amen and hallelujah

13) 14)
Amen

15)
Amen, I would emphasize Also know when enough is enough.

Erik