As far as i remember, the rebbe mentions that most tzadikim can handle whatever the ohr makif bina is, and most people aren’t masig it at all, and that the miteler was unique in that he was masig it, but couldn’t handle sleeping in the sukkah with it.
To say that the chasidim are all farbunden with (one of) the chabad rebbes so that whatever heter he supposedly have would apply to them is halachikally laughable… I’m aware of such explanation when discussion davening late, or copying other established chasidish practices. Yet chasidish poskim go to great lengths to try and substantiate these practices as halachikally valid, not using kabalah to dismiss halacha. One of the best defenses is that a rebbe and his chasidim will spend a lot of time lreparing for davening, be it learning, mikvah, etc, and that’s considered as if they started davening on time.
Yet if he (the miteler) had no halachik, torah laav bashomayim hi heter, he would have been moser nefesh and done what he had to do, of this i am sure. Moshe rabbeinu brought the Torah to Earth, and no longer could it be niskayam according to the specific avodah and middos of a given tzadik as before; yaakov avinu married two sisters, because he understood the ratzon Hashem in that specific situation was such that he was permitted to and even obligated to do so.
After matan torah no such vehicle exists; ain lonu shiur rak hatorah hazos; hanistaros lashem elokeinu vehaniglos lonu…our job is to fulfill dvar Hashem zu halacha.