I'm going off my personal experience, which I admit is probably biased. I attended EWU for two years, have now been at WSU for two-plus years; my wife attended Gonzaga for two years, Walla Walla for two years (MSW); and have family that's attended CWU.
Here's the thing about EWU: not only are there a lot of commuters (there are only four or five apartment complexes in the town and two are brand new whereas Pullman has dozens), but the school also has a much higher proportion of international students and minorities in general than the other universities I've been to. If I had to guess, I'd say most students who attend EWU don't register to vote in Cheney, either because they live in Spokane, aren't citizens, or keep their registration at their home. I personally never registered to vote in Cheney. With regard to living arrangements, EWU is almost more like a very large community college than a traditional university.
I don't think that's the explanation. Cheney is only 6.3% foreign-born, compared to 13.5% for Washington state. That doesn't seem like it can mathematically account for the ridiculously low number of under-35 voters versus the under-35 population of Cheney. And I'm going after Census numbers here, not the school's enrollment, so these are people with residences in Cheney. Maybe many vote at home instead, but I'm not sure why the rate would be drastically higher with in-town EWU students than with in-town students of other schools. Makes it really hard to tell how EWU students voted (almost certainly pretty liberal, but quite possibly less so than any of the other state schools).
EWU is neither a particularly religious nor STEM-driven school. It's easily more liberal in every way that Gonzaga from my experience. Gonzaga is equal parts rich-kid trust funders and poor white Catholics (not many minorities there). There isn't much of an in-between.
For Gonzaga to be conservative, the surrounding neighborhood would have to be 70%+ for both Obama and same-sex marriage. Based on nearby precincts, I'm quite confident that's not the case. I think it's much likelier that Gonzaga boosted up the precinct containing it. There's really no question from the precinct results that Gonzaga's on-campus voters are both Democratic and socially liberal.
They have a very active university ministry program, lots of highly attended mass times, and virtually no fraternities/sororities, whereas EWU and especially WSU have lots of Greek presence. Most Gonzaga students live on-campus, I believe, as the university has lots of really nice and new housing accommodations. Part of that is also that the school is bordered by some really poor, slummy neighborhoods, especially to the north. Logan neighborhood is not a place you want to walk at night if you can help it.
Not sure what you're getting at here -- I get that religious involvement skews conservative, but lacking frats/sororities doesn't.
I've never been to Whitworth, so I can't attest to that one.
This one seems pretty clear to me. Whitworth's precinct contains a couple of suburban neighborhoods too, but the precinct is still more conservative than the adjacent precincts that contain exclusively suburban neighborhoods. Not a ton of voters, but hard to imagine it's over 60% Democratic. It may even be Republican. (although my bet would be Northwest University is the only one that's majority Republican.)
WSU is an ag school, but it's becoming less and less of one every year proportionally. You can easily drive through campus and never see anything related to their ag/animal programs. They have lots of international students as well, but they're much more heavily east and south Asian whereas EWU is more diverse. The school has a large numbers of frats and even has a couple bars on campus. I rank WSU as more conservative than EWU due to the fact that it still does have that ag factor which EWU does not, plus that WSU has easily the highest (among the major universities, anyway) concentration of Mormons in the state.
I can't imagine the ag students or Mormons are a significant enough proportion of the student population to make a pivotal difference. Plus, WSU does have quite a few very clearly delineated campus precincts, and they're pretty damn liberal -- about 70% Democratic, 80% for gay marriage. I imagine that WSU has a higher percentage of students from Western Washington than EWU, especially if EWU pulls heavily from the Spokane metro...that alone almost certainly has massively bigger effect than ag students or Mormons.
I have the least experience with CWU of any of them, honestly; I've only visited twice. My perception is that CWU's a bit like a smaller WSU with more emphasis on engineering than ag. They have feeder programs for Boeing in aviation and aeronautics-related engineering (UW has all the big AE programs, whereas CWU trains for less-technical, more-trade-related positions). However, they do have a few artsy programs, so maybe I'm wrong about them.
Standard caveat that on-campus voters may be different and all, but CWU looks quite liberal: the campus precinct was 77% Democratic and 85% for gay marriage. Not that far beneath UW, especially on gay marriage.
