AP credits count too.
The main thing you should focus on is earning great grades and taking all of the courses required for your desired major. I wouldn’t really recommend taking too many units, unless you know you can handle it. It doesn’t matter if you take more than 60 units – what matters is that you’ve taken 60 units by the end of your last semester in CC. Having more units won’t make your chances better.
I transferred to Cal from BCC, so if you’d like help navigating BCC or anything, feel free to message me!