Could you give some examples of typical tasks that a data scientist does in his daily job, and the must-know minimum for each of the levels (like junior, senior, etc. if there are any)? If possible, something like a Programmer competency matrix.
Becoming a Data Scientist – Curriculum via Metromap is a popular reference for this kind of question.
The Programmer Competency Matrix is just a set of skills, which are more likely to occur when being a real programmer than other skills, they are not a checklist to being a programmer, or for that matter, required to be a programmer; most common way to know someone is a programmer is that they're paid to be a programmer, which honestly has nothing to do with programming skills.
To be a data scientist, do data science.