Is this the same Sebastian Merino b. ~1636 in Aguascalientes?

Hola a todos,

I recently traced my ancestry to Sebastian Merino and Thomasa de la Cruz (Rodriguez?) from Aguascalientes. I descend from them through their daughter Rosa Maria de Arenas who married Juan Salado de Aguilar.
Here is the burial info of my ancestor Rosa Maria de Arenas:

Name: Rosa Maria Arenas
Gender: Female
Burial Date: 29 Aug 1738
Burial Place: Aguas Calientes
Birthplace: Aguas Calientes
Race: Black
Marital Status: Widowed
Spouse's Name: Juan Salado
Father's Name: Sebastian Merino
Mother's Name: Thomasa De La Cruz

Now, at first I thought that this Sebastian Merino was the same Sebastian who was son of Bernabe Merino and Maria Gutierrez, but then I read on his testament that this Sebastian was married three times: first with Juana del Castillo, then to Maria de Jaen and lastly to Nicolasa Ruiz de Esparza. He never mentions his marriage with Thomasa de la Cruz (Rodriguez?).

Here is the link to the testament:
http://www.wikitree.com/wiki/Merino-11

But then, on the last paragraph of his testament he states that a piece of land should be given to his "hijos naturales" Nicolas Merino and Sebastian de Arenas. His last son made me suspect that he has to be somewhat related to my ancestor Rosa Maria de Arenas.

Then, I found the burial info of Sebastian de Arenas (he has the same parents of Rosa Maria de Arenas). I believe this Sebastian de Arenas is the one on Sebastian Merino's testament.
Name: Sebastian Arenas
Gender: Male
Burial Date: 16 Jan 1748
Burial Place: Aguascalientes
Birthplace: Aguascalientes
Race: Black
Marital Status: Single
Father's Name: Sebastian Arenas
Mother's Name: Thomasa De La Cruz

Now, this got more confusing because I ended up finding the marriage record and marriage dispensation of Sebastian Merino (de Arenas) and Thomasa Rodriguez, not sure if it is the same Thomasa de la Cruz. They married on 13 Nov 1689 in Aguascalientes. On his dispensation he is "hijo exposito."

Here is la dispensa:
https://familysearch.org/pal:/MM9.3.1/TH-1-18409-32133-10?cc=1874591&wc=9LDK-W3F:171935001,171974101,175781901

But then if this was the Sebastian Merino who married three times, then he would also be marrying Nicolasa Ruiz de Esparza during the same time, exactly months after his marriage with Thomasa Rodriguez. Thanks to George Fulton's indexes matrimoniales, I found the index of la informacion of Sebastian Merino and Nocolasa Ruiz de Esparza on 22 Nov 1689 in Aguascalientes. This is really really fast to re-marry, not only that but Sebastian's former spouse as stated in the index is Maria de Jaen, not Thomasa. Unless, this Thomasa Rodriguez is not the same Thomasa de la Cruz and therefore mother of Rosa Maria and Sebastian.

Is anyone familar with Sebastian Merino's family and descendants?

I am really confused, I hope I explained myself good.

Thank you.

Roberto Rosales V