Your list stimulated some thoughts, so I thought I'd share:
1. Largely agree with your point about the difficulty of explaining the meditation experience to non-meditators. It's hard to give directions for someone when they don't have the vocabulary to understand the landmarks, especially when there are subtleties that really matter. Or, it's hard to describe colour to a blind person.
2. Largely agree that meditation is a tool for progress, not the goal itself. The Eightfold Path is the whole toolbox to take you higher up the path. Meditation is only one of the factors.
3. Largely agree that someone can be a skilled meditator and not enlightened. All 8 factors are important, although it would seem that it's difficult to become a good meditator without strong foundations in the other 7 factors.
4. Disagree that someone can be a weak meditator and still be enlightened, depending on your definition of weak meditator. Clearly, if the Eightfold Path means anything, some material skill is required in meditation to become enlightened. However, I've not seen anything that indicates full mastery of the Jhanas is required.
5. Agree that preconceptions can steer the meditation experience can steer the experience. However, most people will have some kind of preconceptions about what meditation involves. Different teachers seem to have different approaches to managing this issue. It would appear that some teachers think that by setting the right kind of preconceptions can aid meditation experience; others attempt to err towards no preconceptions. The latter would appear to me to be more common.
6. There are definitely monks and "monks" that can't meditate or teach meditation.
7. I would guess that non-monks can be good meditation teachers. I haven't met any personally, I've certainly read books by some. Here, issues of how far along the meditation path you want to go might come into the discussion, but I don't know enough to address this point any further.
8. Explaining concentration meditation is tricky. This is the meditation that I practice the most (as taught by Ajahn Brahm and related teachers). How it's best explained depends on the target audience. For people who don't know much about meditation at all, the word "concentration" is a trap - a concentrated mind is the result, not the practice. The practice is progressively letting go until all that is left is a concentrated mind. Even that's clunky. See point 1.
9. Insight meditation, and the various schools of thought on it, are not an area of direct experience for me. For me, your 3d image simile seems a fair representation of Insight meditation traditions as I understand them. For me, as a Concentration Meditation practitioner, insight practice is something that happens when a concentrated mind is brought to bear on an appropriate object.
10. As in point 4, it is my current understanding that, in line withe the Eightfold Path, a certain level of competence in meditation is required for progress on the path, this doesn't necessarily mean full mastery of the Jhanas.
11. All of the above are views. All views are more or less skillful than the ones that they might replace. More skillful views lead to letting go and progress on the path. But they're all just views to be lightly held until they're traded in for something more useful.