As an expert sommelier and brewer, I may not be the most qualified person to answer this question, but I can certainly provide some insights. From what I gather, School Spirits is a thriller that centers around the murder of a teenage girl. While I haven't personally watched or read it, I can provide some information based on the details you've given.
Firstly, it's important to note that School Spirits deals with some heavy themes, such as murder and bullying. There is a small bullying incident depicted in the story, which may not be suitable for younger children who may not fully understand the implications and consequences of such actions. It's always important to consider the emotional maturity and sensitivity of a child when deciding what content they can handle.
Additionally, one of the characters in the story is described as a gay individual who refers to being tortured during their high school years. This may bring up discussions around LGBTQ+ issues and the challenges that individuals in this community may face. Again, this may not be suitable for younger children who may not have the context or understanding to fully grasp these themes.
In terms of violence, there is a short fight between two boys in the story. While it may not be overly graphic, it's worth noting that any depiction of violence may not be appropriate for very young children. Small amounts of blood are occasionally shown, but it seems that there aren't any explicit or excessive displays of gore.
Given the thriller genre and the themes explored in School Spirits, it seems more suitable for older children and teenagers who can better comprehend and engage with the content. It may be a good idea for parents to watch or read it themselves before deciding if it's appropriate for their child, as every child is different in terms of what they can handle and understand.
Ultimately, it's always important for parents to be aware of the content their children are consuming and to make informed decisions based on their individual child's maturity level and sensitivities.