We're applying to a few private schools for 6th grade next year - maybe 3, 4 tops. Do you think it's necessary to work with a private school consultant? I feel like I can keep track of this stuff but someone I know recommended working with one. Any helpful tips for going through this process?

I would do it if the outcome is important. It's not about keeping track so much as it is coaching through the process.
I would maybe join the Parent's League, but I don't think a consultant is necessary (I have only been through the processes at K though)
Definitely don't need a consultant. At that age it's largely up to the student and being the right fit. Consultants have zero influence
We had a consultant for K and I am not sure it made that much of a difference. We ended up at our first choice but that was more down to us than the consultant. They help proofread essays, how to handle interviews and generally act as sounding boards. I think if you have some friends who have gone through the process, they can be just as much help to you.