at a CC your major will be whatever you declare it to be when you enroll. No need to change it at your 4-year first. For that matter, your major at a CC doesn’t matter (with exceptions below). Colleges are just going to look at what classes you have taken and if you satisfied the xfer requirements with them. There is a CCC major “Associate Degree for Transfer” that is an exception; this guarantees acceptance into a CSU campus although not necessarily your first choice.
HS is water under the bridge unless you have AP credit; HS classes themselves will not xfer credit at all. As for the credits from your current college, there are 2 completely independent events here. Your CC chooses what classes to give you credit for. But this almost doesn’t matter. You don’t need to graduate from a CC to xfer to a UC, and plenty of people xfer after earning enough units to enter a CC without bothering to get their CC diploma. This way they avoid classes the CC requires that either won’t count at a UC or aren’t needed for xfer. Independently the UC school will decide what to give you credit for. They don’t care what the CC allowed, they make their own decision. They won’t evaluate your units in advance, but you can look on the UC website to see what classes they typically give credit for.
Also be sure to look into the TAG program which gives guaranteed admission at some UCs, and TAP that gives preference for UCLA.