n0mesorah,
“By the fact that I knew the story, obviously I knew that Rav Moshe disagreed with using the Mishkanos Yaakov.”
That doesn’t mean that you know regarding which issues Rav Moshe disagreed with Rav Aharon. As a matter of fact, I am definite that Rav Moshe never read the Mishkenos Yaakov in the original (and in fact agreed with him regarding one issue, albeit for other reasons). Rav Moshe was just making a general statement regarding who was accepted lhalachah.
“If you believe that anecdote was all there was to Rav Aaron’s shitos, you know nothing about Rav Aaron.”
It is irrelevant what I believe, this is what Rav Besser said over many times. In any case, there is no doubt that Rav Aharon followed the Mishkenos Yaakov over the Bais Ephraim. There is absolutely nothing wrong, or shocking, to say that one wanted to follow the psak of his forefathers. All rebbes do so and most poskim follow their rebbeim in halachah (and try to explain their opinions).
“PS What was Reb Tuvya doing at an Hisachdus meeting without Rav Moshe?”
Huh, please reread what I wrote.