UCSD is perhaps the best graduate program in the U.S. for studying Kant. Lucy Allais, Eric Watkins, and Clinton Tolley teach there, and they are three of the very best Kant scholars working today.
I would be wary of Brown, as Paul Guyer is probably close to retirement. Same goes for Indiana: Allen Wood will likely retire in the next few years.
Also, you might check out Princeton, which just hired Andrew Chignell away from Penn.
A new edition of the Philosophical Gourmet rankings should be coming out soon (by the end of the month, I think), so keep a look out for that. Lots of people on these boards are highly critical of those rankings, and for some good reasons. I do think they're useful though, as long as you take them with a grain of salt. The specially rankings are compiled by an anonymous survey of (a selected group) of specialists in the field, in which they are asked to evaluate programs on a scale of 1 to 5. (Anonymous in the sense that we don't know how a given person ranked each department. There is, however, a list of evaluators).
All of the programs you list are strong in German philosophy. However, with the information you've given us, it's hard to say which programs you should be looking at. People who work in Kant and 19th C German philosophy approach it from wildly different perspectives. The best thing to do is probably to try to read some papers from different people in the field and see which approaches align with your own. You could start with some of the professors at the universities you list (Paul Guyer, Beatrice Longuenesse, Allen Wood, R Lanier Anderson, Pierre Keller, Robert Pippin, Eckart Foerster, Clinton Tolley, etc.). Philosophy admissions are extremely competitive, so it may not be a bad idea to apply to many departments with the hope that you can get into at least a couple of them.
There are certainly people working on Kant and German philosophy in German and religious studies departments, but they tend to gravitate towards different approaches than what you'll find in philosophy departments, so it definitely depends on what you're looking for. Keep in mind though, if you go to a German studies department, you will be expected to deal with German literature to some extent and in a Religious studies department, you would likely be expected to take into account other aspects of religious studies as a field.
