First, regarding Kiruv Rechokim, I know that what you said is commonly taught in CHabad circles - that Lubavitch once had such terrible opposition to their Kiruv programs and now everyone is doing it - but it is a total falsehood.
Nobody ever opposed Kiruv Rechokim. It is older than CHabad and older than Chasidus itself.
What was oppsoed is the way Chabad does Kiruv, namely, to send some poor guy out to live among the Goyim and non-religious Jews, which is what was opposed by the Torah leaders, as Rav Yosi bar Kisma says in Pirkei Avos, "Even if you would give me all the money in the world I will not live anywhere except in a Makom Torah."
But in Chabad you have "shluchim" in places like Puerto Rico, where there are zero frum Jews, and zero Judaism, except him and his wife and little kids.
Not exactly what Chazal recommend.
The difference between this and what the Gedolei Yisroel did was they sent groups of people to start Kollel communities to live in different cities, and there was always a pre-condition that the people going to do kiruv would have a "makom torah", either among the Orthodox community of the place they go to, or because of their peer families coming with them. But never would a Gadol send an individual to live among the Goyim and non-religious Jews alone. Never.
That is still opposed, and always was.
Nobody changed their minds about Kiruv, or about Chabad.
The difference between Chabad and SEED is that the SEED program sends (a) people - plural,(b) temporarily, to do Kiruv. That's not the same as bringing up a family and living alone among the Goyim.
What Chabad does, only they do, and it has zero source anywhere in Chasidus. The Baal Shem Tov's "shluchim" were not made to live in Puerto Rico, they went ot teach the Baal Shem Tovs Torahs to frum Jews. Big difference. What Chabad is doing is not Chasidus at all.
The reason the Lubavitcher Rebbe did this Kiruv thing was because of another caricature of Chasidus - the letter of Rav Gershon Kitiver ZT"L saying how the Baal Shem Tov asked Moshiach when he will come, and was answered "When your Torahs will be disseminated".
The Lubavitcher Rebbe decided that because in the Baal SHem Tov's days, that is what was needed to bring Moshiach, so too, for some odd reason, that is also what we need today. Who told the Lubavitcher Rebbe that in our generation, with our needs and our problems, that what applied in the Baal SHem Tov's generation applies ot us too, is beyond me.
In other words, even when a Talmudic sage gets instructions from Moshiach abotu how to bring him, it is not meant absolute, but rather under various condiiton etc. So when Moshiach told the Baal Shem Tov - in his generation - that if the Baal Shem Tov's talmidim would dissemnate the Baal Shem Tov's Torah, then he will come, so the Lubavitche Rebbe decided that means that nowadays if we go all over the world teaching all the non-frum Jews Tanya, Moshiach will come.
Huh?
The Satmar Rebbe calls him a "fool" for this whole idea. So far, nobody has explained what the Lubavitcher Rebbe's excuse is for taking this statement of Moshiach totally out of context.