Eagle custom part attributes
AFAIK, Eagle doesn't have this level of parametrization.  [Neither do Altium, OrCAD.]

If you want to have distinct pin names** in distinct part numbers***, you'd have to make separate library parts.  Copy and paste will do the bulk of the work.

**  OUTA or #OUTA for pin 7
*** albeit they share the datasheet

P.S.  You can tell eagle to draw a proper overbar by using ! sign !FOO! produces \$\overline {FOO}\$