  Previous work relating the flavour variation of the chiral order parameters
$F_\pi$, $<\bar u u>$ and S-wave scattering data, based on chiral sum rules and
chiral perturbation theory at order $p^4$, is extended to include $O(p^6)$
corrections. The finding of a significant decrease of these order parameters,
particularly $<\bar u u>$, with the number of flavours increasing from $N_F=2$
to $N_F=3$ is confirmed, modulo an assumption on the convergence of the chiral
expansion. The connection between scalar resonance physics and the phase
structure of the chiral vacuum is also illustrated on the basis of the linear
sigma-model. We allow for a very general symmetry breaking sector compatible
with softness. The result depends strongly on the input scalar meson masses, in
particular, on the presence, or not, of a light sigma.}
