|Source: Ancestry, Mexico Historical Postcards.|
|Source: FamilySearch, Image 18 of 327.|
|Source: FamilySearch, Image 19 of 327. Sonora Catholic Church Records.|
The document includes the declarations of Miguel Apalategui, who said he had known Vicente his whole 20 years of life; Luis Arevalo, a 49 year old widowed merchant originally from Hermosillo then living in Caborca, who said he had known Vicente for 9 years. Miguel Apalategui also testified that he had known Luciana Parra since she was a child.
Luis Arevalo provided the same testimony in support of Luciana on the next page. As far as I can tell, the two do not appear later in the marriage records for Altar, so perhaps the wedding was called off. At this point, I do not know what happened to Luciana after January 1886. It is still fascinating to see this, and the document does include a clear copy of Vicente's signature along with some names of others who knew him at this stage of his life.
Update - 7 February 2016 - I've now found new documents on Ancestry referencing Luciana Parra and what happened to her after 1886. There will be a new post on this, see February 2016.