You may want to check out Random Encounter.
We encourage families to play together, and we do have a Squire rank for children of our Members. We do expect that Members will properly supervise their children while they are playing. We are also rolling on a RP server.
My main guild back in vanilla had kids of members playing, and it was fine. We made sure that it was known that they were kids, and we had plenty of parents in the guild that made sure that no inappropriate shenanigans happened. It takes a village and all that.