I haven't read the book, but did the Arbiter on purpose leave out his diary? I think he knows that An is a mushroom and took the spore from him ... so tested him with the diary.
He doesn’t know, but he does suspect him. The webtoon has given Lu Feng some soft qualities in comparison to the novels. He is a man with the strongest sense of duty as an arbiter- someone the general public absolutely loathes and he fulfills his job with a cold-blooded demeanor for the most part. By this point, if he knew An Zhe was a mushroom, he would've killed him for being a xenogeneic.
I hope the lawyer friend will get together with the crazy brother and the lawyer will be the top.. I'm not sure if this is expected, but still... i hope.
Same. That spoilt brat needs someone like the lawyer, who isn't afraid to teach him and correct him.