Thank you for these.
On the "why questions" video from the first link, which I've seen before, Feynman's answer only shows that he's used to answering the kind of question asked of him, regarding why magnets repel, and similar questions involving physics.
Yes, he realizes that there are larger issues involved in such questions and their answers, but he steers all the answers and questions back to physics, which to him are the more interesting answers and questions.
Nowhere is there any evidence that his own answers are informed by any kind of reading of philosophical literature or familiarity with the world of philosophy.
Regarding the "Cargo Cult Science" essay. In it Feynman states "even today I meet lots of people who sooner or later get me into a conversation about UFO’s, or astrology, or some form of mysticism, expanded consciousness, new
types of awareness, ESP, and so forth. And I’ve concluded that it’s not a scientific world."
His interest in the question of what is and isn't science, and his answer to it are some of the central things that philosophy of science studies. No amount of physics experiments are going to give you any insight in to that question. To attempt to answer it, as Feynman did, is to practice philosophy of science, which Feynman himself in the original quote which started this thread decries as useless.
The whole essay is really an attempt to engage in philosophy of science, but without any evidence that Feynman is familiar with the field. The result is interesting both because Feynman is an entertaining and capable writer, and because of his obvious familiarity with the practice of science and its ideals. But it's not nearly as insightful as it could have been had he actually undertaken to study the subject academically. It's really an opinion piece aimed at explaining in very general ways some of the practices and ideals of science as Feynman sees them to laymen and other scientists, and almost a polemic on scientific integrity.
Also, it should be pointed out that the philosophy of science studies a lot more than just the questions addressed in this essay. They are important questions, but there's a lot more about science that is philosophically interesting.
Regarding your point about the clarity of Feynman's writing compared to those of philosophers: it's sadly all too true that way too many of them are very poor and obscure writers compared to Feynman. On the other hand, many others are very clear (if usually pretty dry).
When there is lack of clarity, some of it is due to lack of writing ability or interest in clarity (or even wilful obscurity), but in other cases it's due to the specialized knowledge or terminology that is required to understand it -- much like that which would be required to understand a paper in an academic physics journal. If you attempt to tackle such a paper without a great deal of academic physics under your belt, you are likely to be confused. So it is with philosophy, where you'd be a lot better off with some philosophy courses under your belt before you try to make sense of much of it.