Sorry for the late reply.
„Is this whole thing going to self destruct when I exceed 2TB or does the M2P statement of a 2TB limit not consider the current technology “Advanced Format” drives?“
No, that will not happen. It may now be possible to mount more than 2TB with the Raspberry Pi and Raspbian. But we haven’t a 4TB hard drive to test it.
„Seems to be working fine, although I’m having an issue where one of the pi3 cores goes to 100% and streaming stops if I attempt to browse my library by Song, Artist or Album instead of Music Folders (using Android app Squeezer). The other 3 cores appear to be sitting idle, so it seems that either M2P or LMS isn’t taking advantage of the pi3’s quad-core processor. Suggestions to resolve this issue would be welcomed, since having streaming stop for any reason is not tolerable.
This could be a problem with too low energy. If you use a external usb hard drive, you will need a extra power supply to let it work correctly. Additionally I recommend you to activate the Max2Play function „Max USB current“. This setting you can find in the Raspberry Settings of the Max2Play webinterface.