IR typically requires proficiency in one language and study abroad (and/or internship) in an area where that language is spoken as well as basics in another language.
The recommendation to limit any part time job to 6-8 hours freshman year assumes a rigorous college (where getting by with just 1 hour of prep per class period is impossible) and needing time to adjust to the demands of college. In addition to class, you’ll have office hours, study group, review sessions.
On top of this, because you’re aiming for law school, you’ll be expected to rank very high in every class you take and do things that make you noticeable to your professors (attending office hours with good questions is a good first step).
It also assumes that as a freshman you cannot get a very interesting job, so that your time is better spent participating in groups of interests (honors college government, debate society, writing an opinion column in the college paper, etc.) as an investment in the future, so that the following year you have a good shot at a leadership position. At the activity fair, you collect ALL the info of interest then you attend the first meeting for a good dozen and decide which ones will be the best fit for your personality and interests. It’s from showing leadership qualities and contributing to the college community in whatever form you wish that you develop the skills and resume that lead to internships - not just from good grades.
As a sophomore you can probably have a more interesting job than busboy at the cafeteria or library attendant (although the latter is much sought after since it’s a “paid to study” position!) But if your abilities lead to your being offered an unpaid research position for instance, it’s a good investment to take it and adjust work hours accordingly, if you can.
Finally, part of the advantage of being at a top institution is that you’re surrounded by brilliant peers. You want to get to know them, bounce ideas off off them, practice networking. It takes time. But that time is an investment.