I see that law school applications are way down (and LS tuitions are way up) recently. If you're just starting college this fall, the job opportunities (when you'd get out of law school, in seven to ten years' time) actually should be better than they are now. This stuff goes in cycles.
I'm very glad to see IU's "pre-law" program as you've described it: not courses, but advising and (especially) LSAT prep. For law school, major in whatever you like *and can get good grades in*--except that law schools do look (somewhat) favorably on tech/hard science majors and may give them a slight (not large) boost in admissions. Conversely, undergraduate business majors may get slightly *less* respect--but a 3.8-4.0 UGGPA speaks volumes, regardless!
Law school admissions are overwhelmingly a numbers game, so a high UGGPA matters a lot; but because of grade inflation, GPA doesn't help quite as much as it used to, because most applicants to top schools will have high grade averages. That makes LSAT even more important, and you need to prep *seriously* for it. Though I was generally a whiz at standardized, multiple-choice tests, I had to take the LSAT twice; the extra 100-200 hours of practice I put in for my retake were well worth it, but I wish I'd made that commitment for the first one.
1. Don't worry about what law field to specialize in--though if you end up majoring in a hard science as an undergrad, patent law is a possibility later. (I will say that employers of all kinds, some law firms included, love to see people with comp sci majors or minors.)
2. As far as being a "practitioner"--as expensive as law school is for most, you shouldn't be thinking about hanging out a shingle. Individual situations vary, but your best bet for an income that can pay off your LS loans is to go to a top-14 school (top-25 at the outside, as mentioned above), *do well* while there, and get a job with a "biglaw" firm. If you do that, your development as a "real" lawyer will be guided by the people you work for.
[Personally, I'm incapable of doing anything that I think a real lawyer does. I'm a document reviewer: not as lucrative an option as it used to be, but it still pays the bills. OTOH I was fortunate enough not to have to pay tuition, and didn't graduate with a mountain of debt.]
3. Law schools vary. In some schools only a small segment of the class gets well-paying jobs, so the competition is intense. But there really is a very different atmosphere, even at schools that "ought" to be pretty much alike. I recommend visiting as many of your potential schools as possible.
Coming out of law school and looking for employment, you will be judged overwhelmingly on your grades. Doesn't mean that you can't get involved in interest groups, etc., but for most firms GPA, most especially first-year GPA, is king. In line with that, as a general prep for law school I always advise (though many other people disagree) taking LEEWS (leews.com) and reading the book "Planet Law School." (Read it with a grain of salt, and ignore the snarky tone, but read it.)
Most people do best with one or more study partners; if you can, try to get a foreign-born student as one member of your study group (they're often better/more serious students).