Oh, that's a fun one...
..indeed it is probably the ultimate killer configuration, because there is so much going on:
File System (library) => LMS (library) => Whitebear (browser) => MC (library) => MC (controller/server) <=> Whitebear (renderer) <=> LMS (controller/server) <=> Squeezebox
( where => is one way traffic and <=> is two way traffic )
And either a) the File System, b) LMS and Whitebear, and c) MC are on different PCs (in which case you may have LAN bandwidth or routing issues), or alternatively they are on the same PC (in which case you may have CPU horsepower issues, especially if the original file format requires transcoding along the way). Either way it is seriously heavy.
Personally I would take out some intervening steps as follows:
File System (library) => MC (library) => MC (controller/server) <=> Whitebear (renderer) <=> LMS (controller/server) <=> Squeezebox
Plus this: (but only if you really need it)
File System (library) => LMS (library) <=> LMS (controller/server) <=> Squeezebox