  We consider a general energy functional for phase coexistence models, which
comprises the case of Banach norms in the gradient term plus a double-well
potential.
  We establish density estimates for $Q$-minima. Namely, the state parameters
close to both phases are proved to occupy a considerable portion of the ambient
space.
  From this, we obtain the uniform convergence of the level sets to the limit
interface in the sense of Hausdorff distance.
  The main novelty of these results lies in the fact that we do not assume the
double-well potential to be non-degenerate in the vicinity of the minima.
  As far as we know, these types of density results for degenerate potentials
are new even for minimizers and even in the case of semilinear equations, but
our approach can comprise at the same time quasilinear equations, $Q$-minima
and general energy functionals.
