theres a section of the forum where people with nano (small) tanks talk about their special issues
http://www.reefcentral.com/forums/forumdisplay.php?f=75 You can see what they are running for equipment, maintenance routines, how they stock the tanks, and get inspired.
For a 10g a pair of clowns seems unrealistic to me (a 6g is way too small).
www.liveaquaria.com is a good site to learn about fish, they have nice pics and good info about whether the fish is a picky eater, delicate, aggressive, and how big of a tank it needs.
I'd probably use distilled water from the grocery store for evap, and maybe even pre-mixed saltwater from a pet shop for changes. My dorm had no extra space and it would've been weird to tie up a sink with a rodi, my school was cheap though

. A 90 gpd unit is making about 3.5 gallons per hour under good conditions - low flow, uncalibrated rejection, low temp, etc. can slow that significantly. That can be overkill on a ten because in a week you only need a gallon or two for evap and a gallon to water change.
You won't be taking the tank home on spring break, you'll need to figure something else out. An autofeeder and reliable ATO can buy you a week easily.
Saltwater tanks differ from fresh water in that most of their filtration is accomplished by the bacteria that live in the rocks. It's common for converts to feel weird about not having mechanical filtration, but it's def optional and not always beneficial. Google "reef tank nitrate factory" for more info. You're probably best off with 1-2 small fish, and some easy coral like softies, mushrooms, maybe a real easy lps. So the water won't need to be immaculate any way. That'll save you some money on lights too.
Just a couple thoughts. Most of all, make sure the tank fits your life. Your priorities right now should probably be making friends, having new experiences, and studying a little too. If you can fit a tank in after all that, cool; if you can't there's always time after graduation.