Who do I choose as my third reference letter?

[ChessPiece99]

Hi all,

I'm a rising senior at UW Bothell pursuing two majors in Literature and Communication Studies, and I'm presently applying to Master's programs in English, cultural studies, and a few other fields. I have two confirmed references I've already given them all the info they need (CV, personal statements they're helping me edit, samples of work from their classes).

• Possible Reference 1: Part-Time Lecturer with an MA in communication but no PhD who has extensive work experience in the games industry. I took two courses (Interactive Fiction in fall 2019 and Critical Game Studies in winter 2021) with him and got great grades in both classes (3.9 in the first, 4.0 in the second). I hung around after his classes a lot to chat with him about various things and I'm using my final essay for the game studies course as my writing sample for one program because it speaks to a lot of my interests.
• Possible Reference 2: Lecturer that I worked for as a TA during my sophomore year who knows me well. PhD is in English with a concentration in composition and rhetoric, yet she mostly teaches literature classes. I received a 4.0 in the class I took with her on women in literature in spring 2020. Worked with me when I was working on an expansion of my final essay to (successfully) publish in the undergrad research journal at my school. Still in contact with her.
• Possible Reference 3: Not a professor or teacher, but my PI at an education research center I worked as a research and editorial assistant for all of last year. Has two Master's degrees in library science and student affairs, and can speak to my strength in research, copy-editing, and general professionalism as we presented at a conference together. Told the HR lady to send me a return offer (which she did) for after I graduate.

For reference, the other two that I've confirmed and solidified are:

• Confirmed Reference 1: Associate Professor and Associate Dean for Curriculum & Instruction in the college of liberal arts at my school. I took two courses with (Public Humanities in winter 2020 and Post-Colonial Literature in fall 2020) and got 4.0s in both courses. Her PhD is in Asian studies with a focus on literature and she's an affiliate faculty member in the MA program I'm applying to at my current university. This is a prof I have a really good relationship with that I email weekly about things that aren't remotely related to academia.
• Confirmed Reference 2: Associate Professor and Chair of the Literature department. I took three courses with her (a first-year Intro to Humanities course in spring 2019, British Literature in winter 2021, Human Rights and Literature in spring 2021) and got 4.0s in all three. PhD is in English literature and has very similar academic interests to me. She's presently supervising my senior thesis based on my final essay in the British lit course, and I'm using the original essay in question as one of my writing samples.