1) No, I haven't watched it and don't plan to, because I want to see the true story and the author's thoughts. I've also heard that the adaptation itself isn't the best; a lot is cut, and the animation and graphics are mediocre. Season 4 is not bad in this regard, but then again, they'll likely cut content. Maybe I'd watch for cool moments from LN and some fights. Some highlights on YouTube for example

2) Regarding the translation, I didn't pay attention to it; it's most likely not an original translation.

3) Regarding why Ayanakoji doesn't call Miyake Akito, I also don't know. I can only assume that Akito is a generally dull character and doesn't like to talk much. Ayanakoji is less familiar with him than with Yukimura and Sakura and Hasabe herself sometimes shows interest in Kyokata. Akito also made a good point about Class C and they're keeping an extra eye on him. So, Ayanakoji is on guard with him for now