Coops and internships are important. A small difference in ranking is not, particularly for computer science or anything closely related. The difference between a #16 ranking and a #39 ranking really does not matter.
A coop or internship gives you experience working in industry. This gives you are better chance of getting a job later in the company where you do your coop or internship. It also gives you contacts which can be useful for example as a reference. It also gives you work experience that you can talk about in future job interviews. It also makes the whole thing a bit more “real”, in the sense that when you later are in a class, you might see how you can apply some of what you are learning.
There are over a hundred universities in the US with good CS programs. Anything in the top 50 is very good. Prestige also does not matter much in CS. What you can do does matter.
I would not count on staying in the US after graduation. On the one hand visas to work in the US are a political issue, and politics in the US is hard to predict four years in advance. Also, if you do get a permanent resident visa to live and work in the US, the US feels the right to tax you for life even if you later leave the US and return home. The reputation of each company in your home country is something to consider. However quite a few US based high tech companies have major engineering facilities in other countries (particularly India, but also Canada and in some cases some other countries also). I do know a few high tech people from India who had trouble getting a visa to work in the US so they ended up working in Canada (with a Canadian work visa or permanent resident visa). I know a larger number who worked in the US briefly on a temporary visa and then returned to India. We still chat regularly online.