I play on a server with MCA on it, and we have a problem with people despawning. I know that villagers don't despawn, however, multiple wives and children have disappeared with no death messages, in perfectly lit up places that they can't leave. Anyone know what's going on?

They are either being lost or are dying without the death messages. If the players are not online, the death messages will not appear.

They're in a room with no way out, and I'm pretty sure they can't die unless they find a way to suffocate