Because the Baptisms and Confirmations take the place of the Credo. You will have noticed that when they made the Profession of Faith, you joined in, and that it had very similar words to the Credo (for example, “Do you believe,” instead of “I believe,” and “I do”, etc.)
Are Catholics supposed to attend two Masses on that Sunday (Easter Vigil is counted as a Sunday if I’m right)?
The Easter Vigil “counts” for Easter.
Did Jesus rise from the dead at the time of the day when we celebrate Easter Vigil Mass?
The renewal of baptism vows (which is essentially the Apostles Creed in Q&A format) replaces the Creed.
Easter Vigil counts as a Sunday Mass.
In the Early Church, the Easter Vigil used to be a longer Mass that would last from sundown Saturday to sunrise Sunday. People would actually await the resurrection of the Lord. The language still exists in the Exsultet (The Easter Proclamation). Now it’s significantly shorter.
In Egeria’s Travels, the travel diary of a 5th century Spanish nun during her tip to the holy land, she describes the Easter Vigil in Jerusalem at the time. Everyone showed up at the church at sunset (including the bishop) but all she described was prayer and fasting until sunrise. Then they immediately had Mass.
We can’t say if this was universal or not, but it makes more sense than saying they started Mass at sundown and finished it at sunrise. Their liturgies were not radically different from today’s in structure, so I don’t think a 10-hour Mass was possible.