I also like small schools for her, but only those that have a campus environment which is focused on campus life, so she has the maximum opportunity to meet others and make some friends, over time. So I also like the small LAC like Vassar, the women’s colleges like Smith. But I think you and she perhaps may need to pause a moment, and to think about what’s best for her right now, and if that’s living at home and commuting, then that means she only looks at schools within a certain distance of home - and that’s fine, and could help a lot re: the search process.
If you and she (and her doctors) feel that she can live away from home and do well, then how far from home do you/she want her to be? Is it best if her campus is within, for example, a two hour drive, so you can get there if needed quickly, or so she can get home when she needs time away from school? Evaluating these factors can help you narrow your list of schools, and that may help.
Likewise, if living on campus would be okay for her, does her diagnosed health issues allow her to request a single room - no roommate, if that helps? Or do any offer smaller living environments, if that’s what she’d do best in - suites rather than long halls, for example? You could check into the colleges’ options for housing, and rule out any that can’t give her a living situation that works for her, if that needs to be a priority.
You also may want to check into what types of support each school offers. Although all of them have counselors on campus and etc, the reality is that some schools are better prepared to help their students re: mental health than others. Some do a better job than others re: integrating new students into campus as well. This could also help you rule out schools.
Finally, if you and she feel that it’s best that she take a year off from school, so she can have more time to figure out her next steps, then it is completely acceptable to all college admissions offices for her to take a gap year. It won’t hurt her in the future to have done this. She could spend that time doing something of value - learn to play guitar, work, volunteer, learn something she’s never had time to learn, etc. Take the stress off this entire process for now, let her finish out her senior year, then tackle the college thing.