99% sure OT doesn’t do this, but is there a way to lock an audio/midi track sequencing pattern ‘a’ while you switch everything else to pattern ‘b’?
No. The closest you will get to that are the various “transition tricks”:
http://www.elektronauts.com/t/the-crossfader-transition-thread-tips-tricks-etc/4073
and
http://www.elektronauts.com/t/biologiks-part-transition-tip/1296