To be devil's advocate then (although i too am considering scholarships over prestige, as discussed in another thread)...
It's worth asking what you want to do with public interest, careerwise? Would you be happy with something smaller-scale/more local (eg public defender), or are you interested in working with an organization that is more national/international?
Because, from what I've read, prestige does count 'even' in public interest, in getting summer internship positions/ jobs after. Competition for PI spots can be just as, if not more intense than, that for biglaw spots. Many public interests groups (especially the big ones) like to be able to point to the prestigious credentials of their directors and legal advisers to 'prove' their legitimacy to those they are trying to influence, and to attract funders. Another thing is that prestige = connections. A more prestigious school is likely to have alums with more influential positions who will be valuable as mentors and as a source of networking.
And Minnesota in particular happens to have a very well-regarded public interest program
(they are, for example, closely associated with Human Rights Watch), which means they are likely to have a strong network for finding positions in the public interest field.
As a 'national' law school, they will also be better connected to national and international organizations than a regional school.
Of course, I'm not a lawyer and neither is kevdog (I'm assuming), but the implication in his post is right-on: the best thing to do would be to ask advice from people at organizations you've worked for, or better yet people who are doing what you think you want to do (even if that means cold call/emailing). Or, after you get accepted (hopefully), talk to the admissions office from both schools and ask them to get you in touch with their alums so you can hear the spiel from both sides yourself. It might even be possible, once you have your Loyola scholarship offer in hand, to tell that to the Minnesota people and see if they're willing to negotiate (which doesn't seem unreasonable since your stats seem solid for what I remember about Minn).
Basically, what I'm saying is that this kind of situation can be looked at as a trade-off of freedoms: career-freedom (prestige presumably = more and better job prospects to choose from) vs financial-freedom (lifestyle issue, but also freedom to change careerpath more easily).
Either way, good luck!
PS Disclosure: I'm considering Minn too