I live in DC and attended an econ Master's program that places some of its graduates in the International Monetary Fund. I don't think your decision matters too much, and I think you should use teaching quality, and your own interest as a tie-breaker. With the exception of Numerical Analysis, none of these classes sound particularly international-focused or standardized so I would guess they all look about the same to an employer. 

I'd lean towards dropping Economics of Inequality. It sounds way too general and I'm not even sure what someone would learn from that class just by by seeing the title on a resume. That said,  I do want to emphasize that if you should still take it if the curriculum or professor appeals to you.

The skill set of Numerical Analysis may be slightly useful in getting you a job that's working on macro modeling (since macro models rely on numerical approximation to help simulate multiple sectors). But I think these are mostly for technical roles at macro institutions. I suspect it's much less useful at think tanks. Even within macro institutions,  it's not most teams working on it and even then, most early-career people can get offers for these roles with just econometrics and econ theory classes (me being one example).

Social Development and Statistical Methods signal interest in international institutions and Excel data analysis respectively. They both seem good, but you'd have to help your resume readers out by specifying Social Development (thru multilaterals) or something like you did in the post above.

In terms of classes you should look out for:

For statistics, I'd rate econometric classes quite highly. Take the highest-level undergrad econometrics class you feel you can do well in. If your school has macro-themed electives like time-series econometrics, it may help to take one. These skills also generalize really well even if you leave research entirely. 

For econ theory, I would see if your school has a class that uses the Krugaman, Obstfeld, & Melitz textbook on international economics. Class titles may go by International Finance (for the first half of the textbook), International Trade (for the second half), or International Economics (for a less detailed look at the whole). Personally, I found this textbook dense (especially the finance part) and I'm not sure if it's something I could pick up on my own. So a class here is definitely useful.

For institutional knowledge, I would highly rate classes if you have professors who worked at think tanks or multilaterals in the past AND they are teaching on a related topic. 

I would choose stats! I'm not sure how these courses would affect internship applications, but I was an economics major for several years and always found the statistics and econometrics classes to be the most interesting and useful. I think a lot of people who end up working in economics use less of their theory background and more of the data analysis skills they learned in stats / econ / coding classes. Econ classes that focus on a particular theme rather than a theory or tool of analysis in my experience operate more like history classes, teaching you a lot of interesting information about the topic but not really providing concrete methods that you'll use again -- it's more like general critical thinking skills. 

That said, I don't think there's an obvious answer, I'm just saying what I enjoyed. If you're particularly excited about one in particular that might be the right choice! Good luck with the class :)