Regarding 1—in the original context in Sefer HaMitzvot, it could be explained that it refers to proper behavior…
But in chapter 1 of Hilkhot De'ot it’s harder; he speaks explicitly about traits and tendencies, and at the end of the chapter says that this is a commandment, “to walk in His ways,” and he lists all the traits….

In my opinion, the Mussar movement was definitely an unusual success, with very clear and innovative techniques, until the Chazon Ish came along and unintentionally killed it. All the yeshiva high schools, without exception, in Lithuania, the U.S., and Israel, were founded by people from the Mussar movement, who were convinced of the justice of their path and of their ability to use the methods of the Mussar movement to cope with modernity. Hebron too, from the outset, was not aiming for Haredi isolation, but rather to produce rabbis who would work within the new settlement without fearing modernity, as Shlomo Tukachinsky shows.

True, the Mussar movement had various psychological techniques, but the shared assumption that a human being is a psyche (a soul) united them all. What brought them down was the Chazon Ish’s use of the famous Maimonides that a person is influenced by the people of his place, and that therefore the only way to deal with modernity and Zionism is flight to the deserts—in other words, the yeshivot. The Chazon Ish’s use of this Maimonides, which of course they could not reject, expressed the superiority of sociology over psychology. No matter what psychological tools they used, a person would still be influenced by the people of his place. As a result, all the methods of the Mussar movement were abandoned, and its institutions moved into Haredi isolation.

The only factor that offered a principled sociological alternative to the Chazon Ish was Rabbi Kook. But Rabbi Kook consciously crossed the line from the perspective of Haredi tradition and became modern. From Rabbi Kook’s perspective, the hidden religious side of Zionism makes religion the place of Zionism, and therefore religion has nothing to fear from Zionism. You can see this in mechanistic education that emphasizes the fact that Zionism is a divine movement, and that army service is not only a threat to religious identity but a way to participate in the highest service of God. In Rabbi Kook’s view, the ones who fail to understand their place are דווקא the secular people who believe that the state is secular and Western by nature, instead of seeing it as the throne of God in the world, as it truly is.

One could argue that there is also a Modern Orthodox alternative, but so far we have not found anyone who dealt directly with the sociological problem raised by Maimonides.

As far as I know, the Chazon Ish did not express opposition to the Mussar movement in general, but rather to Novardok in particular.
His opposition was mainly to that movement’s piercing psychological probing, which sometimes caused emotional crises and prevented real progress. Also, to the suspicion cast on every motive as stemming from arrogance and therefore invalid, despite the benefit that could be drawn from it. And likewise, to a large extent, to the abandonment of traditional paths, together with group pride and contempt for those who followed them.
(As explained in the omitted section of Faith and Trust, and as Chaim Grade described so well in his book The Yeshiva)
Even though, when choosing a brother-in-law, he himself chose from among the well-known students of Novardok.
As for the branches of the Mussar movement from Kelm and Slabodka, I’m not aware of any special opposition to them (and most of today’s Lithuanian yeshiva world defines itself as continuing in their path).
And even if there was some opposition, it was negligible.
The Mussar movement as a strong and influential movement declined over the years because of changes in the generation,
and aside from external features of the “greatness of man,”
not much remains.

Moishe,
I didn’t say he was against them, only that his argument against integration into the Zionist state, which was based on the above Maimonides, in practice pulled the rug out from under their central underlying assumption. Rabbi Israel Salanter’s innovation was that the human being is a soul (psyche), and with suitable methods one can break into it and direct it toward the service of God. The Mussar movement is perceived as a dark movement, but in fact it was an optimistic movement. It believed that with its methods religious Jews could be modern without harming their faith. As a result, the Mussar people were not afraid to open vocational educational institutions alongside the yeshiva institutions and to integrate their graduates into central branches of the modern economy.
The Chazon Ish did not come to argue with them. His main concern was dealing with the new settlement, as Benny Brown shows in his biography of the Chazon Ish. But the conclusion the Chazon Ish reached was that anyone who participates in the Zionist enterprise will always offset his fear of Heaven in favor of building the Zionist enterprise, and he used Maimonides’ idea that a person is influenced by the people of his place in order to explain his position and persuade the traditional public of it, after the Holocaust, when they stood bewildered before the new Jewish state. His use of Maimonides pointed to the superiority of sociology over psychology, and thus pulled the rug out from under the feet of the people of the Mussar movement. If Maimonides is right, then all the psychological exercises of the Mussar movement won’t help, and a person will always follow the people of his place. True, this Maimonides was known to the Mussar movement, but it was always perceived as a local matter and not as a sweeping claim. The Chazon Ish turned it into a sweeping claim, and against the Chazon Ish the people of the Mussar movement had no real counterargument. As a result, the Mussar movement lost its vitality and was dragged along after the Chazon Ish’s move toward isolation in the yeshivot.

Sounds like a flimsy theory from the outside.
In Haredi terminology, things simply don’t work that way.
Even if the Chazon Ish quoted Maimonides’ words a thousand times, it wouldn’t have changed anything.
Besides the fact that it is not known that the Mussar movement focused in any special way on integration and openness to general society, or alternatively on Zionism,
except for the exceptional case of the elite yeshiva high school of the Alter of Slabodka, and some of his students who were individually connected to Zionism, like Rabbi A.I.A. Kaplan, and Rabbi Yechiel Yaakov Weinberg, who served as heads of the Rabbinical Seminary in Berlin. From such cases it is hard to conclude that the Mussar movement had any special inclination toward Zionism.

Yes, I know the Haredi closed-mindedness. Whatever lies outside their field of vision simply doesn’t exist.
Even if you bring them the example of Hebron in the 1940s, the network of yeshiva high schools run by Rabbi Bloch, head of Telz Yeshiva in Lithuania, and more—it won’t satisfy them. It simply doesn’t fit the Haredi template created by the Chazon Ish, so it can’t be that it existed.
It also doesn’t help that you write that they were thinking about coping with modernity and therefore operated in various places around the world such as Lithuania, the U.S., and Israel, whereas the Chazon Ish was dealing with Zionism. From their standpoint, if the Chazon Ish pulled the rug out from under them, then apparently they leaned toward Zionism.
It also doesn’t matter that you explain that the Chazon Ish did not argue with them, but rather that the very argument he presented in the name of Maimonides (and which reappears in every self-respecting Lithuanian sermon) raised a question that their psychological method could not cope with.
If things deviate from the Haredi template, then apparently they are mistaken.
Fine.

Since the discussion here has drifted toward the influence and status of the Chazon Ish in the Haredi public,

I can’t resist linking here to the following item:

The head of the Rabbeinu Chaim Ozer yeshiva in Bnei Brak, Rabbi M.Tz. Berlin, warned his students that any student who participates in the demonstrations of the Jerusalem faction will be expelled from the yeshiva.

Notice his powers of persuasion and rhetoric. Notice how he knows how to explain his position against participating in the demonstrations (an impressive capacity for expression and reasoning that almost approaches the marvelous abilities of Rabbi Michi):

“There is not a single student who cannot grow and become the great Chazon Ish. And therefore here in the yeshiva no student may go out to any demonstrations. Because anyone who goes to demonstrations has no chance of becoming the Chazon Ish.

“And therefore, anyone who thinks he won’t become the Chazon Ish has no place in the yeshiva.”

Amazing.

Attaching a link:
http://www.bhol.co.il/125582/%D7%94%D7%A8%D7%91-%D7%9C%D7%90-%D7%97%D7%AA%D7%9D-%D7%90%D7%91%D7%9C-%D7%94%D7%96%D7%94%D7%99%D7%A8-%D7%9E%D7%99-%D7%A9%D7%9E%D7%A4%D7%92%D7%99%D7%9F-%D7%99%D7%A1%D7%95%D7%9C%D7%A7.html

Y.D., my dear, don’t get angry,
but I’m having trouble understanding the logic by which you reached such a far-reaching conclusion.
First, you assume that the aim of the Mussar movement was integration into local culture.
On the basis of the proof that if the Chazon Ish mentioned the well-known Maimonides, then surely his intent was to undermine the Mussar approach,
and if he speaks about inward Haredi consolidation, then apparently the method of the Mussar masters was integration into general society.
And second, you bring evidence from isolated cases such as Telz Yeshiva, which was not a flagship yeshiva from the standpoint of the Mussar movement, but only later attached to the movement’s yeshivot.
When you bring a theory with two such significant sides—especially a claim of such decisive influence—you need more than flimsy proofs dependent on interpretation, and more than evidence from isolated cases within the movement.
(Especially when there is significant counter-evidence from Rabbi Israel’s famous kollel, which was the source from which most of the well-known Mussar figures emerged, the students of Rabbi Israel Salanter.)
By the way, personally I don’t see any special value in inward Haredi isolation. Still, truth is dearer to me than all else, and I can’t accept a claim that supports my views but is detached from reality.