I do not know who the Ygnacio Sánchez de Mendoza who is having children in Jalostotitlán is, but it looks like he might be a brother of Andrea's. This would need to be verified.

Name: Maria Antonia Sanches De La Bas
Gender: Female
Christening date: 03 May 1729
Christening place: NUESTRA SENORA DE LA ASUNCION, JALOSTOTITLAN, JALISCO, MEXICO
Residence: Jalostotitlan, Jalisco, Mexico
Father name: Ygnacio Sanches De Mendosa
Father birth place:
Age of father:
Mother name: Maria Masemiliana De La Bas
Mother birth place:
Mother age:
Batch number: C60320-3
Date range: 1721 - 1735
Record group: Mexico-VR
Film number: 279255
Collection: Mexico Baptisms 1700-1900

I also found a child of Andreas but you will have to verify the information on the film, you might already have this information. Wow almost nine months to the day! You might want to look up the batch number on FamilySearch.org, IGI to see other individuals from that town that were christened during the Date Range of 1721 -1735

Name: Joseph Antonio De Salgado Sanches
Gender: Male
Christening date: 10 May 1725
Christening place: NUESTRA SENORA DE LA ASUNCION, JALOSTOTITLAN, JALISCO, MEXICO
Residence: Jalostotitlan, Jalisco, Mexico
Father name: Juan De Salgado Y Villasenor
Mother name: Andrea Sanches De Mendosa
Batch number: C60320-3
Date range: 1721 - 1735
Record group: Mexico-VR
Film number: 279255
Collection: Mexico Baptisms 1700-1900