There is no specific GPA requirement or EC’s specified to be invited into the Honors college, however in the past few years it is usually the Regents scholars (top 1-2% of applicants) plus additional exception students so at least the top 5% of Freshman applicants. You can always apply after your 1st year at UCD.
If you look at the 75th percentile in GPA and Test scores for admitted Freshman, would need at the minimum an UC GPA of 4.2, SAT scores above 1400 and ACT scores of 33 or higher.
I would not worry about making choices now until you have some acceptances in hand. You are putting the cart before the horse. Get accepted to UCD and the other UC’s, then decide which school would be a better choice.