I don't think this would count as plagiarism, because a particular technique/quote from a particular text used in different essays will remain the same and will have the same effect, meaning different essays may raise similar points with respect to their analysis. Essentially, you're developing a response from someone else's study notes. It's not like you are using a response written by them as a basis for your own. Plagiarism is determined (and possibly penalised) when there is a high level of similarity between your response and someone else's response.
However, with that being said, you should definitely try to raise your own points in addition to the other person's points or (where possible) replace some of their points with some of your own, as that would considerably reduce any risk associated with plagiarism. Alternatively, and in addition to writing in your own words, you can modify the structure (such as order of points as well as number of paragraphs) of your response in such a way that would create a clear distinction between your response and someone else's.
I hope this helps!