I think it depends on the context.
Inkling can refer to a specific numbered version of an advanced Little One, or Big Little One, while an ADLO or ADLOs would be an abbreviated or short form of saying Advanced Little Ones, while Advanced Little Ones could refer to a more generalized description of a group of advanced Little Ones containing a mix of numbered Inklings and their turned victims who carry the traits of an Advanced Little One or ADLO but should the group contain only Inklings then one might be allowed to use the term Big Little One to refer to said zombie as said zombie was indeed at one point a true Little One and not an instant Advanced Little One as seen in the victims of Inklings.

Or fuck it, we call them Inklings and everyone gets it.^w^