Christine, it is very simple, because the ban on Dorje Shugden itself is illogical to begin with, so all the actions that follows it will be illogical.
Take for example the very basic thing, which is your question number 4. If Zong Rinpoche was a demon worshipper in his previous life, then why is there even a yangsi??? The very fact that they recognize Zong Rinpoche's incarnation is proof that they DO NOT BELIEVE that Dorje Shugden is a demon or evil, but have no choice but to follow the CTA's rules. That's why it's ok to accept Zong Rinpoche's incarnation as long as he doesnt practice DS, which means, as long as he doesn't give trouble to the monastery. If he did, then they would have cast him out like how they did with Trijang Chocktrul Rinpoche.
These are really a bunch of ungrateful people. Kyabje Trijang Rinpoche have given so many of these lamas supreme knowledge. I guess for these people, Dharma is cheap and politically correctness is more important. The comforts of this life is much more important that samaya. Too bad for them i guess.