Users can send questions in the app and receive direct answers back to them.
For example person 1 send a question about where the nearest shop is and I ( the creator of the app) can send them a direct message that only they can see).
I’m not sure exactly how, but i think it’s possible. It wouldn’t look pretty but I think you could do something with a rich text & have a pre-set number of rich text inputs on the app that you could go in & manually input on the sheet (or separate app which reflects in the sheet). You could set it up as a form & have the visibility set so that the next input only shows if the previous has been filled otherwise it stays invisible or something like that. You’re going to have to get creative & ‘hack’ it I think. They have a built in chat feature but that would go to everyone using the application.
The comments component would probably work as long as each user had their own record somewhere in the app. Something where each user would only see their own record and would have their own comment component keyed to their own email. Then some sort of admin section where you can access all of the user records and go through each user to see questions and comments. Still not great and maybe building your own system like @carrabre said would work better for you. That or just use email.