Your #4 is a tricky one. In developing the life admin and then small business systems, we’ve settled on a pattern that seems to sit best with most people.
Which is that you’ve got some parent thing – using PowerBI, being a CPA – and that this should be recognised as the parent.
It is the thing with an ID.
And then learning about the thing is a child of this thing.
Rather than learning about stuff being a parent, and PowerBI being a child.
I think it’s one or the other, and as long as you decide and be consistent, you should be right.