for the derivations of the (anti-)BRST symmetries, similarly, we have to derive the [*universal*]{} SUSP [*dual*]{} unitary operator (and its Hermitian conjugate) for the (anti-)co-BRST transformations for the sake of completeness. We have accomplished this goal in present investigation. Second, the existence of the SUSP [*dual*]{} unitary operator (and its Hermitian conjugate) provides the alternatives to the DHC and DGIRs that have been invoked in the derivation of the nilpotent (anti-)co-BRST symmetry transformations within in the framework of AVSF. One of the highlights of our present investigation is the observation that the SUSP [*dual*]{} unitary operator and its Hermitian conjugate turn out to be [*universal*]{} for [*all*]{} the [*Abelian*]{} models that have been considered in our present endeavor. Third, the Abelian 1-form theories (that have been considered here) are [*intresting*]{} because these have been shown to provide the physical examples of Hodge theory. Fourth, we have found out the (anti-)co-BRST symmetry transformation for a [*new*]{} model which has [*not*]{} been considered in our earlier works on the superfield approach to BRST formalism \[22-25\]. We have obtained, for the first time, the (anti-)co-BRST symmetry transformations for the modified version of the 2$D$ anomalous gauge theory. Thus, it is a [*novel*]{} result 