While whizzing through the code looking for spots to fixup, I came across an error in my previous hardware inference.  It is in the sendLCDnybble_F68F routine.  I had believed that port D was used for the LCD OC2/1 lines on PDb1,0.  However upon closer inspection I see that it is in fact in those positions of the keyboard column latch at $8000 -- /not/ Port D.  Well, I supposed that answers my question about by the LCD R/~W line was on $8000 bit 2, and what might be at bits 1 and 0.