  RbFe$^{2+}$Fe$^{3+}$F$_{6}$ is an example of an antiferromagnet with charge
ordering of the octahedrally coordinated Fe$^{2+}$ and Fe$^{3+}$ ions. As well
as different spin values, Fe$^{2+}$ ($S=2$) and Fe$^{3+}$ ($S={5\over2}$)
possess differing orbital ground states with Fe$^{2+}$ having an orbital
degeneracy with an effective orbital angular momentum of $l=1$. The resulting
low temperature magnetic structure is non collinear with the spins aligned
perpendicular to nearest neighbors (S. W. Kim \textit{et al.} Chem. Sci.
{\bf{3}}, 741 (2012)). The combination of an orbital degeneracy and non
collinear spin arrangements introduces the possibility for unusual types of
excitations such as amplitude modes of the order parameter. In this paper we
investigate this by applying a multi-level analysis to model neutron
spectroscopy data (M. Songvilay \textit{et al.} Phys. Rev. Lett. {\bf{121}},
087201 (2018)). In particular, we discuss the possible origins of the momentum
and energy broadened continuum scattering observed in terms of amplitude
fluctuations allowed through the presence of an orbital degree of freedom on
the Fe$^{2+}$ site. We extend previous spin-orbit exciton models based on a
collinear spin structure to understand the measured low-energy excitations and
also to predict and discuss possible amplitude mode scattering in
RbFe$^{2+}$Fe$^{3+}$F$_{6}$.
