Instead of trying to check the boxes for an official minor, why not use your elective space to take technical and non-technical courses that are of interest to you and potentially useful for future goals? The official minors may give some suggestions about what may be of interest, but choosing courses of your interest without being restricted to them may be more satisfying to you.
Japanese is considered a more difficult language for English speakers, so it may require more courses/credits to get to a specified level of proficiency than in some other language like French or Spanish (unless you already have some proficiency from high school or as a heritage speaker that will place you into a more advanced course to start).