The colonial times were also the Casta times, thus unlike post independence Mexico, the costumes did not differ much from those in Spain, therefore to understand them a little you can always check the culture and customs of the peninsula (also influenced by other cultures like the Muslims) As for the Spanish in Mexico and their families (mix or not) many times the marriages where prearranged, and those families in any given town knew each other very well, thus most of their kids would grow up knowing each other, many were even family, we can see a lot of marriages between relatives.

The Hacienda culture that you refer to, born around the 1850's, this is after the colonial times, with Mexico finally consolidating more or less as the country we know, the social status changed from castas to money and power, the structure of the Hacienda (not the unit measure any more) was taking shape to open it for new villages and towns (their government that is), by these times average folks would be more close to the "hacendados" and would get influenced by them, passing these customs from the rich to the low income class would become latter what we know as "Mexican Culture", Bailes, Bodas, Bautismos, Quince Años (something that I despise by the way), Confirmaciones, etc. I don't mean the actual ritual but the "fiesta" itself. The Haciendas were notorious though in the way they manage their wealth, by the time of the civil war "Revolución" most people from the Haciendas have moved to the big cities leaving behind their style of life now evolved as "Vida Pueblerina", This times are precisely what we considered the "old times", this is what our grandpas and great-grandpas remember, and thus what we tend to have as the "back in the days customs".

All of it is very picturesque though, The book of my town called Amecatl has some letters from one of the local Hacendados describing their style of life, the parties, mettings, horse races, etc.

when my Dad went to Jerez, Zac in 1936 he said when they went to town everyone gathered at the plaza. There would be music, the girls would walk in one direction and the boys would walk in the opposite direction and the Mothers, grandmothers and madrinas would sit on the benches to make sure no hanky panky went on. Dad said if you saw a girl you liked you would try to pass her a note. One girl passed my Dad a piece of candy and his grandmother saw it. She jumped up and took it from Dad. She told him that girl had gotten the candy from a witch and it had a spell on it that would make my Dad come back to Jerez and marry that girl. His grandma would not have it. Dad was 16. Couple who were courting also walked arm in arm but were watched to make sure everything was proper..