That's a completely normal practice in Catholicism.
That's not quite true. Catholics pray for their ancestors and pray to the saints when not praying straight to God.
This isn't true. All the saved are saints, even if they aren't canonized. It is reasonable to assume that they are in such a state and thus engage them in intercessory prayer like any other saint.
Right, but Catholics don't know who are the saved. So, they pray to God and the saints for their ancestors because they might not be saved.