Where I could obtain the history or any records of the chapel in the San Pasqual Valley?

I suggest you contact Dr. John Johnson at the Santa Barbara Museum of Natural History. He and his colleages are very knowledgeable about the native americans and their early history, and often do geneological and other research for individuals and tribes. The contact information is:

Museum of Natural History Santa Barbara Museum (www.sbnature.org)

2559 Puesta Del Sol
Santa Barbara, CA 93105
(805) 682-4711