Why do we give foreign aid?

[President Tyrion]

Firstly- because it tends to have a far higher return on investment (economically, and in terms of satisfying people's basic needs) than other foreign policy instruments, such as military interventions

I don't disagree with your point as a whole. However, empirically, military spending is actually the most efficient way to stimulate short term economic growth through government spending: more so than welfare, healthcare, or public works (welfare and public works are both much better long term solutions, of course, and healthcare costs the government money, but life is a worthy cause, in my opinion). As a Democrat, it's not necessarily in my nature to want to uphold American militaristic spending, but it is flat out wrong to say that it is an inefficient use of money. Of course, this effect is on Americans and mostly only Americans. Foreigners are thrown under the bus by America, but then again, when are they not?

[President Tyrion]

Firstly- because it tends to have a far higher return on investment (economically, and in terms of satisfying people's basic needs) than other foreign policy instruments, such as military interventions

I don't disagree with your point as a whole. However, empirically, military spending is actually the most efficient way to stimulate short term economic growth through government spending: more so than welfare, healthcare, or public works (welfare and public works are both much better long term solutions, of course, and healthcare costs the government money, but life is a worthy cause, in my opinion). As a Democrat, it's not necessarily in my nature to want to uphold American militaristic spending, but it is flat out wrong to say that it is an inefficient use of money. Of course, this effect is on Americans and mostly only Americans. Foreigners are thrown under the bus by America, but then again, when are they not?

I take your point on military spending and job creation. However, domestic job creation is not among the traditional foreign policy objectives. Those are rather securing / promoting access to resources & markets, containing terrorism, controlling immigration, etc. If you do a cost-benefit analysis related to any of the a/m objectives, you will typically find foreign aid superior to the use of military force (which nevertheless may be required in specific situations).
Since you appear to have quite a good overview on available data and research: Is there any statistics available on the income US educational institutions generate from students from developing countries (including India and China),  and associated job creation in the US?
How much domestic spending on primary and secondary education has the US been saving by attracting immigration from developing countries? it was massive in the late 19th to mid 20th century, when most immigration was European, I wonder how the ratio is nowadays..

Brilliant questions, and well beyond the scope of the data I was looking at. Sorry, I don't have an answer for you.