  The neutrino mass and dark matter (DM) problems are addressed in a Standard
Model extension where the type-II seesaw and scotogenic mechanisms coexist. The
model features a flavour $\mathcal{Z}_8$ discrete symmetry which is broken down
to a $\mathcal{Z}_2$, stabilising the (scalar or fermion) DM particle.
Spontaneous CP violation is implemented through the complex vacuum expectation
value of a singlet scalar field, inducing observable CP-violating effects in
the lepton sector. The structure of the effective neutrino mass matrix leads to
constraints on the low-energy neutrino observables, namely the atmospheric
neutrino mixing angle $\theta_{23}$, the Dirac CP-violating phase $\delta$ and
the absolute neutrino mass scale $m_{\rm lightest}$. In particular, in most
cases, the model selects one $\theta_{23}$ octant with $\delta \simeq 3\pi/2$.
Moreover, the obtained lower bounds on $m_{\rm lightest}$ are typically in the
range probed by cosmology. We also analyse the constraints imposed on the model
by current experimental limits on charged lepton flavour violating (cLFV)
processes, as well as future projected sensitivities. It is shown that the
Higgs triplet and scotogenic contributions to cLFV never overlap and that the
interplay among Yukawa couplings, dark charged scalar masses and mixing leads
to a wide parameter-space region compatible with current experimental bounds.
We investigate the scalar and fermion DM parameter space of our model by
considering relic density, direct-detection (DD) and collider constraints. For
scalar DM the mass interval $68 \ \text{GeV} \lesssim m_{\text{DM}} \lesssim 90
\ \text{GeV}$ is viable and will be probed by future DD searches. In the
fermion DM case, correct relic density is always obtained for $m_{\text{DM}}
\gtrsim 45$ GeV thanks to dark fermion-scalar coannihilation channels.
