C.S. Lewis said that it didn’t bother him that Christianity has links with earlier religions: What would have bothered him was if it didn’t have links with earlier religions. The fact is, you can find echoes and connecting points between Christianity and all the other religions both ancient and modern, and it is this fact which validates rather than invalidates Christianity. If a religion is not only true but more true than all the other religions, then it should connect with all those other religions at the points where they are true.
The Catholic understanding is that there are echoes, connections, and similarities among Catholicism and all the other religions because Catholicism fulfills them and transforms them from within. The other religions are partial truths. They are hints and guesses at the truth. They are the riddles and Christ is the revelation which completes them and answers their questions. The Hebrew religion was the one which most perfectly pointed to the coming Christ, but each of the pagan religions and philosophies in their own way—some better than others—point to and prophesy the coming of Christ.