I’d really appreciate serious researchers’ thoughts on this Sebastián Pérez question.

Having reviewed the reconstructed family trees, baptism and marriage dates, and the various dispensas, it has become increasingly apparent to me that Sebastián Pérez, husband of Isabel de Ávalos, and Sebastián Pérez, husband of Leanor Ruvalcaba, were likely the same individual.

A father-and-son relationship has been proposed for these two men, but the chronology makes that relationship difficult to accept. Based on the estimated birth dates of Sebastián Pérez's sisters, Ana Pérez and María Burgueño, both of whom appear to have been born before 1600 (having children born as early as 1615), the Sebastián Pérez who married Isabel de Ávalos would have been too young to have been the father of all three siblings if the two Sebastiáns were separate generations.

A more plausible explanation is that there was only one Sebastián Pérez. He first married Isabel de Ávalos and, following her death, subsequently married Leanor Ruvalcaba. This interpretation seems to fit the available facts and chronology considerably better.

It also makes more sense for the Sebastián Pérez who married Leanor Ruvalcaba to have been born closer to 1600 rather than in 1635. The 1635 birth date appears frequently online, but I have not been able to locate a primary record supporting it. More importantly, the dispensa associated with Leanor Ruvalcaba's later marriage to Juan Pérez de Ornelas provides chronological and familial context that seems difficult to reconcile with a Sebastián Pérez born as late as 1635.

Under this "single-person" interpretation, Sebastián Pérez does not die a relatively young man who is barely forty. Rather, he appears to have lived a long life, marrying twice and having families with both women. His marriage to Leanor Ruvalcaba would therefore have occurred later in his life, which is entirely plausible given the chronological evidence.

In my view, treating the two Sebastiáns as the same man who married first Isabel de Ávalos and later Leanor Ruvalcaba provides a much more coherent explanation of the reconstructed genealogy, the estimated birth dates of the children and siblings, and the evidence contained in the dispensas than the proposed father-and-son relationship.

Sebastián Pérez

Born: circa 1600-1605?
Died: c1675

1st wife: Isabel de Ávalos

Children:

• Nicolás Pérez, b. 1627

• María Burgueño, b. c1630 m. 1649

  ***Last known contemporary mention of Isabel de Ávalos:
  4 June 1649 — Sebastián Pérez and Isabel de Ávalos were padrinos at the baptism of Felipe de Espinoza.

2nd wife: Leanor de Ruvalcaba

Born: c1639
Died: 1697

Children:

• Sebastián Pérez, b. c1659
• Inés Pérez, b. 1661; d. 1715
• María Burgueño, b. 1666; d. 1720
• Antonio Pérez, b. c1670; d. 1703
• Marcos Pérez, b. 1674
• Diego Pérez, b. c1675; d. 1752
• Felipe Pérez, b. c1675; d. 1734