Question about UC Transfer Statisitcs by major, uc gpa, and seeking advice for application

Hi, I’m gonna apply for UCB, UCLA, UCD, UCSD, UCSB next year. I have some questions about the transfer process. I will apply as statistics or math major, and I just look up the statistics for admitted transfer students for my major. I realize my overall GPA will below the 25th percentile. I will finish my IGETC this summer, and I will have 1 more math class left to take for next year. My overall GPA would be around 3.65, and my major GPA is 4.0. I’m only applying to this 5 school, and I’m afraid I will only get into my tag (Davis). I still have some question, hopefully, someone can answer my questions.

  1. I'm planning to take a few cs course next year, but I'm not too good at cs. If I take 2 or 3 cs course, and end up with Bs. Would this affect my admission to UCB and UCLA? Those cs courses are not required, and every class list in assist is As. Is this a bad decision?
  2. I just hear there is a regent scholarship thing, how can I get invited? Based on my GPA, is it impossible to get regent for a school like UC Davis and UCSB? Do I have to win some competitions or do some impressive things to get invited?
  3. I don't have many extracurricular, but each extracurricular I have been doing since the beginning. I'm a math tutor (10 hours per week), and I go to the gym (6-7 hours per week). I've taken some Coursera courses (an online platform) relate to my field (5 hours per week). I will have some time before applying, what should I do to improve.