I just came across a 2007 article by Daniel T. Willingham “Critical Thinking: Why is it so hard to teach?” Critical thinking is very commonly found in lists of learning outcomes for general education or even at the institution level. In practice, it’s very difficult to even define, let alone teach or assess. The article is a nice survey of the problem.
I like the questions you lay out as a possible framework for critical thinking. What really caught my attention though was the discussion of action as part of intelligence. There is a word used by liberation theologians in regards to action as a result of thinking - praxis. They talk about the consideration of much of what you cover in your six questions, but then push into the real world in terms of what action will your thinking push you into, then an evaluation of the results of that action in the context of your thinking. Repeat as necessary.
One of the aspects of critical thinking that you didn’t cover is when it is needed. Not all of our lives require the effort of critical thought. It then becomes necessary to think critically about when and where to think critically. Robert Sawyer in his Webmind books suggests that the work of consciousness is to refrain from instinctive action and thus spark critical thought.