As the others have pointed out, usage of terms like major and minor vary from institution to institution. As it happens, my undergraduate uni (in Canada) did have specialist, major, and minor tiers—but I can't guarantee those terms mean exactly the same thing at the universities you're considering. Generally, the difference is in the number of credits you need to complete within that program. A major requires more courses than a minor, and specialist requires more than a major. In all cases, there is generally a mix of required courses and lists of courses you can choose from, though selection tends to be more limited for minors since you don't really go beyond the core courses.
As a general rule, if you want to go to graduate school in a certain field then you should do whatever undergraduate option involves taking the most courses in that field. It's really something you can't work out in more detail until you pick a university. Then you can contact the department, tell them your goals, and ask them which of their programs is likely to be the best fit. There's no one size fits all answer.