The pavilion without the mailboxes sounds like it could be a picnic area, and that may be eligible. The mailbox pavilion is a utility for the community, infrastructure where one can pick up and/or drop off mail, so it typically isn’t seen as eligible.
Single family private residential property, SFPRP for short, is an ineligible location, and new buildings typically aren’t eligible, unless they have unique architecture/shopping center and are not SFPRP..
It sounds like this is a new suburban neighborhood that is being built, and many times, the developers do not add many POIs that may be eligible. It may be a struggle to find other things that are eligible once the neighborhood is fully built, but one thread to look at is the one for rural Wayfinders, which is more for areas of low-density than just rural: Tips for Rural Nominators