From the trusty Catholic Encyclopedia: "it may confidently be said that, as the result of centuries of speculation on the subject, we ought to believe that these souls enjoy and will eternally enjoy a state of perfect natural happiness; and this is what Catholics usually mean when they speak of the limbus infantium, the "children's limbo."
The citation you produced refers to the Limbo of the Fathers... the actual Limbo. As you can see the Limbo of the Infants isn't doctrinal.
Didn't someone quote this source earlier in this thread? I remember it also said something to the effect that they would enjoy a state of perfect happiness BUT that it was not the full "beatific" experience of heaven in the presence of God Almighty. Does it really say that?
More RC double-speak. The quote you cite doesn't say "heaven," does it? It doesn't say infants will be in the presence of God or see His face.
"Perfect natural happiness." lol. I prefer the supernatural happiness of heaven.
I bet those babies supposedly in Limbo would prefer that, too.