Short answers, pulled from the story.
Juan Bautista de Toledo was a Spanish architect, born around 1515, who trained in Italy under Michelangelo and Antonio da Sangallo the Younger. He is best known as the original architect of El Escorial, the royal monastery complex commissioned by Philip II of Spain, as well as major works in Naples including the Strada di Toledo and modifications to the Castel Nuevo.
In 1561, Philip II appointed de Toledo as Arquitecto Real responsible for the full town planning of El Escorial, covering the monastery, the village, and La Granjilla de La Fresneda. He laid the cornerstone on the 23rd of April 1563 and supervised all architectural and public works until his death on the 19th of May 1567, when Juan de Herrera took over and completed the monastery in 1584.
Yes. On the 18th of December 1546, Pope Paul III appointed him Deputy Coordinator Architect for St. Peter's Basilica. On the 26th of February 1547, Michelangelo personally named him as successor to Labacco, instructing the Florentine mason master Niccolo to follow his orders. He also worked on the Palazzo Farnese courtyard under Michelangelo.
In Italy he was known as Giovanni Battista de Alfonsis, while in Spain and Naples he used the name Juan Bautista de Toledo. Researchers established both names belonged to the same person because documents from the two cities share identical handwriting. His full name may have been Juan Bautista de Toledo Alfonsis.
During his time in Naples as Maestro Mayor de Obras Reales en el Reino de Napoles, de Toledo designed or rebuilt the Strada di Toledo (later renamed Strada di Roma in 1870), the church of St. Giacomo degli Spagnuoli, square bastions for the Castel Nuevo, a large palazzo at Posillipo, Castel Sant'Elmo, and several fountains.
Juan Bautista de Toledo died on the 19th of May 1567 in Madrid. He was buried in the choir of the primitive Convento de Santo Tomas, Iglesia de la Santa Cruz, in Madrid.