The BCL is unusual because the output buffer is NOT nested in the global feedback loop.
After that, it is closer to a PPA buffer than an M3.
http://cdn.head-fi.org/8/87/87579c0c_lovelycubecircuit01.jpg
PPA buffer is nicer, and if one were so motivated they *could* convert the PPA pretty easily. Leave out R4, jumper R3, and set gain with R5&R6.
The O2 is just off-the-shelf op amps. Not really much for the designer to worry about with class AB. The JRC4556 is actually pretty nice (as far as op amps goes) for driving headphones directly. Its not the amp that people dont like, its that his fanboys came around and said "this is right, and things that dont even begin to operate under the same principles are wrong." There is certainly a place for the O2, but there needs to be a fight so that people can still design things and learn for themselves.