Historically, Limbo has been offered as a theological speculation regarding the fate of infants who die without baptism. It's not unreasonable speculation. Today, the Church is simply saying that theologians are gradually moving away from this speculation, and the Church is stating with greater force that the fate of infants dying without baptism is an open question.
I'm betting not. I have heard it with my own ears, John Paul II and Mother Teresa speaking of aborted babies in heaven. Because as I posted the Church teaches that the Church is bound by the sacraments but God is not. I have a feeling they will edge closer to the idea of heaven for unbaptized babies. I could be wrong though.