I think all of this and more could be part of a "sane" search engine that would give the power to the user. I don't use DDG because many of the extensions I mentioned above are not available for it, and also because I simply don't trust them.
Given Mozilla's mission and their success with reviving FF, I wonder if a search engine is on their to-do list in the future.
Also, I could be wrong, but I don't think there's a lot of folks there with relevant experience, so that's hiring a big new team to bet the farm on. Not my cup of tea (but then, I'm risk averse)
Mozilla's marketing team, for the, oh, ca. 10 billionth time, decided it was high times to once again foist something on Firefox users that none them wanted, needed, or asked for. To the surprise of Mozilla Marketing (but no-one else) it did not go too well.
[0] https://en.wikipedia.org/wiki/Cliqz#Integration_with_Firefox