  Following our previous work of 1905.10745 [hep-th], 2003.11217 [hep-th], we
study heterotic interpolating models $D$ dimensionally compactified with
constant background fields that include the full set of Wilson lines and radii.
Focusing on the phenomenoloically viable supersymmetry restoring parameter
region, we analyze the pattern of gauge symmetry enhancement and the
representation of massless fermions. We obtain the set of cases with the
exponentially small cosmological constant. Our analysis does not depend on
non-supersymmetric endpoint models of interpolations. A part of the moduli
space of interpolating models is in one-to-one correspondence with the
counterpart of toroidal compactification of heterotic superstrings.
