If you major in IR/IS, you usually have to choose a thematic option (e.g., national security, development, etc.) and a regional focus (e.g., East Asia). Often, international economics is one of the thematic options, or you can focus to some extent on international economics via an economics major.
As for spreading yourself out vs. focusing on a region, in part, this will be determined by your primary regional interest and any requirement to choose a regional focus as part of an iR/IS major. Also, it would be desirable (if not required) that you spend at least an academic year studying in a country in which your chosen language is spoken in order to acquire an adequate level of proficiency. This will limit opportunities to acquire the same level of proficiency in more than one language. If you choose an East Asian language, you should be prepared to commit to studying it for more than the typical two or three years that many IR/IS or area studies programs require. You should also consider why you’re picking a particular language and what you expect from that----is it just to read scholarly literature or media in that language? is it to interact and do business with political and business leaders in the country/region of interest? Is it to interact with locals or work “in the field” in a particular country/region? Is it to analyze documents or other media? Is it to interpret/translate? Is it to deal with speakers or media in a particular technical area? Also, don’t study a language just because you think it will improve employment prospects. The interest in the language and culture should be there, too. You’ll find that in many countries, international business will be conducted in English, and your counterparts will speak it almost as well as or better than a native speaker.
As for French and Spanish giving you “more global reach,” that’s true in the sense that they are more geographically widespread, but consider what types of jobs you might do. You mentioned government or intelligence-related work. OK, specifically, what kinds of work in those areas might you realistically do. For intelligence analysis, you might need expertise in a region, too, so if you did French, what region? Africa? North Africa? France? With Spanish, you’re limited to either Spain or Latin America. It’s less unlikely that you’d have regional expertise in both French and Spanish-speaking areas. Even in the Foreign Service, you won’t necessarily be posted in an area where you speak the language. Again, for these languages, the same considerations apply as noted above in terms of the purpose for which you might use the language.
So, in answer to your questions about French and Spanish vs. East Asian languages and regional specialization vs. global reach, you really can’t answer those without consideration of what your intended use is for the language and what types of work you realistically see yourself doing.
You mentioned that you’re already learning French, Spanish and Chinese. Those are all good, but lots of people are studying those. What about some of the other critical languages----Portuguese, Turkish, Persian, Hindi, Russian? The Language Flagship programs might interest you. http://www.thelanguageflagship.org/
As for IR/IS vs. Economics/Area Studies, imo, economics seems to be viewed as a more solid and serious, and thus, “respected” discipline. It’s also a quantitative field and offers additional opportunities in business careers. If by any chance, you attend a public landgrant university, don’t overlook coursework (or, even a major) in ag and resource economics. The field covers many areas relevant to international affairs—trade, development, environmental economics, etc. As another option, think about how many international issues intersect with environmental issues—natural disasters, climate change, water resources, famines, etc.—and think about pairing economics with environmental studies (or, even, in geology or geography).
Also, see my posts in these threads:
http://talk.collegeconfidential.com/college-search-selection/749245-undergraduate-foreign-policy-schools.html
http://talk.collegeconfidential.com/other-college-majors/902677-political-science-vs-international-relations.html