i think when you have a drain of a pmos meeting an nmos you do generally have to have some way of defining the DC point... which in a single ended case is usually done by the next stage or feedback or something.
in differential circuits, with differential outputs, a convenient way to do this is CMFB (detect the commonmode by averaging the differential output and use that in a control loop).
In the single-ended output case there is no "CM" as such, just the output DC level which might need controlling, so it these cases it is not termed CMFB as your are not feedback the common-mode.