Loading Whitebear didn't change SqBx visibility. I noticed LMS said it was defaulting to iTunes, so I changed that. Coincidence or not, the SqBx became visible, but I got an error preventing its use. That was a while ago, so I don't remember exactly what the error was, I think it was a socket error I've never seen before. Most of the problems I'm having (with two different renderers) aren't MC's fault. I really like what MC purports to do, and the forum has been surprisingly responsive with good suggestions (special kudos to John who helped me with ripping). But making it all work reliably may require more time and effort with a collection my size than I'm going to be able to put into it. I'm not sure it will even be possible with my particular equipment configuration (if reliability is included).
For what it's worth, I'm now on Windows 8.1. Windows 9 is rumored to be within hailing distance and a major improvement. I'm hoping networking becomes more transparent, but in any event, Logitech has said it will no longer support SqBx after Windows 8. So even if MC, Gizmo, Whitebear, NetGear, LMS, Synology, Onkyo, et all begin to cooperate, things may fall apart again after another Windows upgrade.
I will continue to stumble along, and probably even try MC 20, while keeping an eye out for SqBx replacements or other possible equipment changes.
PS, I temporarily uninstalled Whitebear, but it didn't disappear as an LMS plugin. Though in admin mode, I still see no way to "apply" the change permanently after removing the check on a plugin.