You are going to have an uphill battle getting into any highly selective business program. Math rigor/grades are incredibly important to admission to business schools. Most business schools will want to see precalculus at the very minimum. Knowing you had the opportunity to pursue higher math and that you chose a math elective (statistics) instead won’t help your cause.
I don’t know enough about California schools to venture a guess on your chances. If your high school is indeed a feeder school for your top choices, your guidance counselor can probably give the most realistic odds at admission. She will know if others with your profile are often accepted.
In general, though, your ECs can’t compensate for your academics. Don’t look for them to “make up” for a weaker academic record. First and foremost, admissions officers are looking to admit students who they believe will excel academically at that school. ECs can help when they have more academically qualified applicants than spots, but academic rigor/performance is the number one consideration.
My 2022 is at a mid-tier business schools, which has been very impressive to me. I attended a T10 business undergrad and have an MBA, and I am blown away by the programming, counseling, and access this school provides. The curriculum is also very current. It’s probably ranked 40+ places lower than my own undergraduate program, but I have no concerns about it.
Because your high school is a feeder school, I would apply to those reach schools, but I would look at the rest of the list to create more balance. Look at the kind of mid-tier school that my 2022 attends and you will see that it has all the same clubs, classes, and opportunities that your reaches have. Not only that, but I bet if you look at who recruits there, you will be surprised at how similar that list is to the list at your reaches.
Go somewhere will you will be at the top of the heap and where they might be interested in investing (time and money) in your entrepreneurial pursuits. As an aspiring business major, I am sure you understand ROI and debt, and realize the precarious financial position you would be putting yourself in if you are overleveraged as an undergrad. You should save those financial resources for starting your business or for applying to a top MBA program.
Good luck!