Murder of Crows discussion

It’s a young adult murder mystery so I didn’t expect all the gore and typical stuff I like when I went into this book, I was more so keeping my eye out for a believable plot with good characters and a good mystery. The first book was pretty mediocre and I still feel the same about the second.

Because this is a YA book series, I think a lot of things are allowed to get overlooked.(view spoiler)[ Such as the extreme delay in the allergic reaction Rosa had (It was brought up many times but never actually addressed when it was confirmed it was from the smoothie the day before. Also why she was in the hospital for so long clinging to life. After receiving epinephrine and going to the hospital to get checked out, there’s no reason she should be on the brink of death for days following.), how even though Keith changed his name he was able to get the job he has (guiding young children through their life especially after the trial with the twins and Orchid’s testimony went public), how Vaughn and Oliver are still able to live their double life and not be caught (there’s just no way), and with so many deaths happening at this school, they for sure would not be letting the courses go on just as planned. (hide spoiler)]

In the beginning of the book (view spoiler)[ before Rusty is killed, he says, “Oh, it’s you,” as if he knows who his attacker is. This was never explained in the end. Was there another layer to the murder that we didn’t know about? We were never officially told how he died. Coroner ruled it was of exposure but Plum said he saw a head wound (there’s no way the coroner missed that). So what’s going on there? How did he actually die and why was that not revealed to us? Would it just create too many plot holes? (hide spoiler)]