For a dual major as joedoe said the only difficult one to consider is CS. But if you want to add it as a minor that’s easy as I understand it. Adding a minor typically means adding about 3-5 classes to your 8 semesters which isn’t too bad. My suggestion would be either dual or masters, minors don’t really effect the interview a whole lot as a dual would. It’s best for people people who personally want to learn more about a subject and therefore that being the case, just take the single course you wanted without risking your gpa with the other 4 classes you didn’t want.
Your DD will love RPI. My son absolutely loves it there and is thinking of either dual CS or Masters in CS. He is currently a CSE with a 3.8 after his first semester. He’s taking data structures next semester so we’ll see how he does.