A whole bunch of different issues are being jumbled up here:
The roommate’s (and other friends’) behavior: Was it a “mistake” or not? It really doesn’t matter, It happened. It could easily happen again, too. It is not easy being the roommate of a friend who is mentally ill. The roommate may have overreacted, the roommate may have made a reasonable judgment in terms of a cost-benefit analysis, or the roommate may have overreacted sort of on purpose because the situation was stressing her out and calling 911 got her relief for weeks, and counting.
Nonetheless, there’s an important point here. The OP and her daughter have as a primary goal getting back to the “normal” college dorm living situation. But that situation may no longer exist, whatever the college does. If the daughter’s presence makes her roommates uncomfortable – whether or not they admit that, even to themselves – then going back into the dorm and into that room may not make anyone better off. I may be wrong about this, but I suspect focusing on getting back into the dorm is completely the wrong focus.
The college administration’s behavior: The college bureaucracy is acting defensively. Butts are being covered. In other breaking news, the sun will rise in the East tomorrow.
Is the college discriminating against a student with an illness? Sure. If you want to sue, be my guest. But I would gladly place a number of bets – Protocols are being followed, carefully. Those protocols have been developed by people whose job it is to protect the college from things like discrimination claims. Suing, or even threatening to sue, will provoke the college into even more defensive action. It will take years and hundreds of thousands of dollars to get to the point where a court would even rule substantively on the question whether the college’s protocols were appropriate or not. Going the litigation route would be a selfless thing the OP could do for future students in her daughter’s predicament. Even if it succeeds, it will do nothing for her daughter except make her a professional litigant for a few years.
Is the daughter at risk of harming herself?: This is a really important question. According to the OP, a whole bunch of professionals are saying “no.” That’s wonderful news.
But I, too, know families who were completely unprepared for their adult children’s suicides. It wasn’t because they were unaware of their children’s mental illness or in denial about its severity. It was because they thought it was being managed successfully, with lots of therapy and lots of medication and complete, enthusiastic cooperation. It had been years – not months, not weeks, really years and years – since there had been any known attempt at self-harm. Things were going great.
Should the daughter finish college and graduate ASAP?: This is really the only question where the OP can have any meaningful input. If the daughter is really only a couple of months from finishing college, and it’s not going to interfere with her treatment, I would lean to getting college over with now, and then focusing on some stable situation for continuing treatment and learning how to manage her condition.
If trying to deal with college is making things more difficult for the daughter, then by all means prioritize her health over finishing college. That’s not even a close call. However, my mentally ill college roommate was able to hold it together well enough to graduate on time, and he slid into a federal government job with unparalleled psychiatric benefits that served him very well in the long run. College was an inherently unstable environment for him. I wished at the time his parents would get him the hell out of there for a few years. However, realistically his life was improved enormously in the medium- and long-term by finishing college, putting it behind him, and starting to work on building a stable adult life elsewhere.