Birthday Party Etiquette

Hello. My husband has 7 co-residents. He is close with the guys but not the girls. We’ve hosted the entire group at our home several times for dinner parties and cookouts. Most of the co-residents are single women in their 20s. They get together a lot without us (wineries, bars, late nights). Only 2 of his co-residents are married and have children. We are close to the ones with children and spend more 1:1 time with them. We are planning our child’s birthday party and my husband and I aren’t sure if it’s better to invite all the co-residents to this sort of thing or just the two we are close with. We would tell them no gifts are necessary and just to come enjoy some food. But overall the guest list is small as it’s mostly a few family members, neighbors, and a couple close friends with their kids. Appreciate any advice.