Here’s a way you might be able to fulfill the requirements of the assignment.
The Japanese surrender document was signed on the USS Missouri. You can google “USS Missouri” and find a page (somewhere, I know there’s one out there) for a “veterans of” listing. Look up some of the veterans (and their wives, since they will also have been ‘young adults’ of the time) and see if you can find email links to some of them and present your interview questions. You may only receive a single response to scores that you send out, so send as many as you can.
You could also look up ships involved in the Iwo Jima campaign, Okinawa, D-Day and other notable naval engagements. If you know any of the Army and Marine battle groups involved in other campaigns, such as Operation Torch (invasion of North Africa), the Battle of the Bulge, Sicily, Anzio, Guadalcanal and other campaigns, you should be able to find some of the same lists of veterans and surviving family.
I’m sure that Canadian, British, Australian and New Zealand veterans have similar social networks, and since they speak the same language (more or less) you could get an international flavor to your response if you can contact some of them as well.
I would also recommend Jewish Holocaust survivors, who often speak of their own experience to schools and other groups, and who would be very happy to participate, I’m sure.
You may get lucky and find a sympathetic secretary / organizer of one of these groups who can help distribute (and endorse) your questionnaire.
Good luck. Tell your teacher from me that this is an excellent assignment. I hope you put the effort into it that it deserves.