I think that one reason you are having trouble finding a path is that you are looking for a performance degree but your family is excluding the possibility of a BM, whether at a freestanding conservatory or affiliated with a college/university.
Others have clarified the terminology and degrees: conservatory, school of music, music department, BA, BFA, BM. BS. A BM program will be 2/3-3/4 music with a performance focus, and a BA will be 1/4-1/3 music classes, with more academic focus and sometimes a performance component at some level.
If you look at liberal arts colleges, you are usually looking at a music department with a BA program (NOT always) and performance in extracurricular organizations. There are usually no auditions for admission, but a music supplement can be submitted with recording, music resume and recommendations from music teachers. Auditions happen in the fall for extracurriculars. For a BM program, there are usually auditions for admission, often after prescreens.
If you continue to look at schools that have a good reputation for their BM programs, be aware that opportunities may be less for the BA students since the best teachers and performance opportunities go to the BM students.
There may be exceptions to all this but you have to really dig and I realize you are doing that. One thing to look at with BA programs is whether credit is given for lessons and performances- this is really key to the orientation of the program. And whether there is any performance component to academic music classes- so check the actual course descriptions. Look at the faculty lists and see if there are excellent performers on faculty or staff.
**The fundamental problem here seems to be that your son wants to do music, and would at this moment be happier in a BM program most likely. But parents do not support this path. This issue comes up ALL the time. I just read another post about vocal performance majors, which has some articles that are relevant for all music parents- check it out. And study the Double Degree Dilemma essay well!
Please believe us that it is okay to focus on music as an undergrad!! This can lead to many paths in and out of music. The undergrad years should really be free of the kinds of career stresses that lead to the idea of a “more practical” degree. Music majors do very well getting into med or law school, they can do MBA or accelerated nursing, they can apply to any job that requires a bachelor’s and to other grad school programs. Music schools are well aware of career pressures and students do outreach, take an entrepreneurship class, and can intern in music organizations and other non-profits. My kid can fundraise and write website promotional materials and concert programs with the best of them 
The long term perspective is that paths are very flexible. The kid who spends all his time on music as an undergrad, at a freestanding conservatory, may end up in grad school doing Medieval Studies or Accounting. The kid who opted to do music through private lessons and extracurricular performance may catch fire doing gigs and go to a grad conservatory program. I know doctors who got their BM and still play in a regional orchestra.
The article on the VP thread uses the word “magical” to describe the years spent in music study. Avoiding big debt is important, but otherwise, I hope you and your husband can find it in you to support your son in music studies at whatever level he chooses. In that case, many of the schools mentioned would be great for him. You may find a well-respected BA program with great music but chances are it won’t present the kind of immersive experience in music that your son now craves.
With a few exceptions, you may be banging your head against the wall trying to find something that doesn’t exist in many places, while the answer may be right in front of you in terms of your son’s wishes.
Encourage him to apply to different options: any BM program that he loves, including freestanding conservatories; and an academic BA program that has a good music department, and maybe a state University too (SUNY’s are great for music, but a BM might be better there). Your son can change and grow in the coming months and having several options will make you all a lot happier. He can decide in late April senior year and in the meantime, you can all work to come to terms with what he might choose.