I went to Catholic school for 12 years, graduating just as V2 changes were being implemented. I was taught by Dominicans that limbo was one possible explanation for where unbaptized innocent persons, including babies, go when they die, that it was permissible to accept this as a possibility, but that we have no definite knowledge and that they are entrusted to God’s mercy, and whatever He decides is perfectly right and just. by the way, in case anyone asks, I also studied bible history beginning in 4th grade and until graduation 3 class periods a week were spent on scripture, and 2 on church history. this was in addition to class on religious doctrine and morality.