During the Mass, when Evita is receiving Communion, she responds to the priest with "Amen". However, in a Tridentine Mass, nothing is said by the communicant before receiving the sacrament. The practice of saying "Amen" does not begin until the Second Vatican Council.
Eva Peron's shoes change during the waltz scene with Che. Apparently Madonna began filming with higher heels, fell, and, fearing for her unborn baby, switched to lower heels with a clearly different strap set-up. Her hair also changes.
After Evita & Juan Peron are married they walk outside the church and there is an army of well wishers and photographers who snap their picture. In real life Evita and Juan were married with the most absolute secrecy with the only guests being Evita's mother and one of Peron's ministers. Certainly no photographs were taken at the event.