I do have a large collection, and I have given it a great deal of thought, especially the interaction with my Squeezeboxes. Squeezebox will not let me search by Composer. The search fields I can use are Genre, Artist, Album, Song and Year. As I generally choose the classical music (the Genre) I want to listen to first by composer and second by performer, I have conflated those two into the artist field (see in screenshot where a work is by "Bach Heifetz" - btw another limitation of Squeezebox is the amount of text that can be displayed at any time). I have also handled the Bach (J.C.E.) issue you raise.
If an album includes a single artist performing works by multiple composers and I want to hear the entire album, I can select one work from the album and then use features of the Squeezebox software to "assemble" the entire album.
In the end, my system works with Squeezebox; however, I do not understand why when I try to sort according to the "Artist" field in JRiver, the "(Multiple Artists)" tracks appear first. "(Multiple Artists)" is not part of the Artist field. If I wanted I could sort by Album Artist, but I have expressly chosen not to do so.